At what temperature do fleas die?

Summary

Adult cat fleas die in temperatures colder than 46.4°F (8°C), and hotter than 95°F (35°C). However, the low-end extreme for immature fleas is 55.4°F (13°C). During winter, adults can survive in cold temperatures while living on a warm-bodied host.

FleaScience

Img 1 Environmental conditions needed for all life stages of the cat flea to survive.

Details

Cat fleas can survive from egg to adult in temperatures between 55.4°F and 95°F (13°C and 35°C) Fig 1.

Cold Temperatures

Low-End Extreme

Adult Fleas

Temperatures below freezing are lethal to adult fleas . They’ll die within five days at 30.2°F (-1°C) Fig 2. At 24 hours, there’s mortality in 20% of emerged adults and 72% of pre-emerged adults. Fleas can live up to ten days at 37.4°F (3°C). Survival significantly increases when temperatures exceed 46.4°F (8°C), where nearly half of emerged adults stay alive for 20 days.

46.4°F
37.4°F
30.2°F

Fig 2 Percent of emerged adult fleas that survive (y-axis) across 40 days (x-axis).

Immature Fleas

Flea eggs and larvae are more susceptible to cold temperatures than adults. The immature stages require temperatures of at least 55.4°F (13°C). At 50.4°F (10°C), eggs hatch within 12 days, but first instar larvae die 10 days later.

Winter Survival

In the winter, near-freezing temperatures kill fleas living outdoors. While frost kills fleas, not all will die in winter. Some immature stages develop in the freeze-protected dens of wild animals. Adults will survive on their warm-bodied hosts, such as dogs, cats, raccoons, or opossums. And, of course, fleas living within heated homes will survive.

do fleas go away in the winter

Michelle Bender

Img 1 Fleas can survive winters indoors, in animal nests, or on warm-bodied hosts (e.g. raccoons).

Some geographic locations year-round warm and humid climates. As a result, fleas can thrive nearly all year long. In Florida, for instance, fleas continue developing even in the winter months from November to March.

Hot Temperatures

High-End Extreme

Adult Fleas

Any temperature above 95°F (35°C) is lethal to adult fleas. They’ll die within two days unless relative humidity exceeds 75% Fig 3. Fleas can’t survive outdoors when temperatures surpass 95°F for more than 40 hours a month.

Fig 3 Days it takes (y-axis) for 90% of unfed adult fleas to die at various relative humidity percentages (x-axis) while temperature is kept constant at 95°F.

Immature Fleas

Flea larvae also die at 95°F (35°C). They’ll live long enough to form cocoons and complete their pupal-imaginal molt, but 100% will die within their cocoon.

Washers and Dryers

Fleas, of any stage, can’t survive the laundering process. To kill fleas on clothing and bedding, it’s recommended to wash the items for 10 minutes at 140°F, and then dry at the highest heat setting. Multiple factors will prevent survival. They’re exposed to extreme heat, extreme dryness, flooding, detergents, and physical tumbling action.

References

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Discussion

  • Nancy July 27, 2016, 10:02 pm

    I’m having a flea problem. I read your article about how temperature over 95f Will kill fleas. For clarification how many days of heat inside the house does it take to kill fleas, larvae and pupa? I’M trying this method while i’m waiting for an IGR. Please please advise. Thank you for your time.

    • Adam Retzer July 27, 2016, 10:27 pm

      Nancy, heating a home isn’t a viable method to kill fleas indoors. Adult fleas live on pets and won’t be affected. The eggs, larvae, and pupae develop within microhabitats of carpeting. These areas have their own microclimate, where temperate and humidity are held constant, and they’re relatively unaffected by the surrounding conditions.

      At 95°F, unfed adult fleas die in 0.5 to 9.5 days, depending on the relative humidity (RH). Take a look at Fig 3. Eggs won’t hatch at 95°F unless RH exceeds 75%. Larvae can survive long enough at 95°F to spin cocoons, but they’ll die within the silk structure. In home environments, larvae live for around 7 to 11 days before cocoon formation.

      • Nancy July 28, 2016, 1:41 am

        Thank you Adam for your prompt response. I should have asked this question before doing this. I think I made an even more mess than what it was. I have had my room since Saturday in between 99 – 102 degrees with RH in between 32-38. I have a room temperature reader. I’m just desperate to get rid of them because they are driving me nuts. Oh dear, once again thank you for your time.

        • Sarah August 2, 2016, 6:44 pm

          We have the same issue. We have an empty shipping container that we could put items in and heat to necessary temperature. We would put in mattresses, couch, etc. before moving the items to our new home. Do u think this method would be effective?

  • Krista August 8, 2016, 10:03 pm

    I am having a very difficult time getting rid of fleas after living in a house with them for several months. Could I bag up my children’s stuffed animals that can’t do in the wash and leave them in the hot car for a couple days to kill any fleas on them?

    • Adam Retzer August 9, 2016, 8:51 pm

      Hello Krista, that strategy should work in the summer heat. However, it’s unlikely that fleas are on the stuffed animals.

      • Louise June 13, 2017, 10:49 am

        Thank you for all this information! Grateful over here. How long do I need to leave my stuff in a hot car? I went on vacation and stayed in a place with fleas. Put my suitcase in the trunk and went straight to a laundromat otw home (1.5 hour drive). Then had the car professionally vacuumed before picking up my clothes from the laundromat. The only things I did not wash are a leather jacket and a bathing suit. All these things (including the laundered clothes) are now in my car–the unlaundered in the trunk and laundered in the backseat. Could my car have gotten them either the trunk from my suitcase or the front seat from my sitting there? How long do I need to leave them in the hot car? It is 93 degrees outside today!

        • Adam Retzer June 19, 2017, 2:38 pm

          It’s unlikely that fleas got onto your belongings, but not impossible. I’m not certain the exact amount of time needed to kill the fleas. However, 1-2 days in a hot car should do it.

      • Vashti Campbell November 29, 2017, 9:35 am

        Hi. But do flea eggs stick to stuffed toys?

  • Steve August 12, 2016, 5:44 pm

    Thank you for your article on flea survival in hot and cold temperatures. We have been cursed with fleas and are now moving to a new home. We have to be sure we’re not taking any fleas, including their eggs or pupae. We have a large shipping container for moving and we were thinking of lightly packing it with home items then heating it to a temperature that would be sure to kill all flea stages. What temperature do you recommend and for how long?

    • Adam Retzer August 12, 2016, 11:15 pm

      I’ve replied to a similar question previously. You can find it here.

  • Rhonda September 26, 2016, 3:24 pm

    Hi, Your site has definitely been the most clear and helpful in my dealing with fleas. I’ve had pets always and only had fleas twice in 15 years. I’d count myself lucky but right now is one of those times (the other, a sick kitten). My sweet 12 year old Aussie was diagnosed with liver cancer some weeks back and, while I’m very grateful for a nearly miraculous turn-around in that respect, he got fleas while he was so sick. I’m sticking to totally non-toxic approaches due to his health and mine (I get migraine from the most mild of chemicals, even regular laundry detergent). I’m doing regular baths, bagged up all rugs (they’re getting a seven to twelve month hiatus), diamotaceous earth, washing everything I can, temporary dog bedding washed every day, hardwood floors vacuumed washed and DE even got two dehumidifiers going full-time (thanks to your information) so RH is consistently below 50% and often as low as 40%. It’s been 3 weeks and I’m still getting bitten, seeing the occasional one even in my “clean” bed (dog does not sleep with me) and yesterday I discovered hoppers in the car in his backseat hammock. So discouraging even though I know it takes time.

    My questions are two: do I have a real chance of getting rid if the fleas going this route? and, I am able to get the interior of my car up to 50C (making RH very low, like 20-30%), how long would it take to kill all stages at this temperature? Maybe it’s not possible.

    I’ve done two, five-hour shifts of 40-50C in the car over the last 24 hours and washed the hammock. It’s a black interior so it’s impossible to see fleas. I’m hoping against hope that the fleas (larvae and pupae) were contained in the hammock and that any strays were cooked.

    Thank you.

    • Adam Retzer September 27, 2016, 11:53 am

      Rhonda, sorry to hear about your flea problem. If the infestation has gone unchecked for a while, you may have a difficult time ending it without employing some chemical methods.

      Vacuuming and laundering pet beds and rugs are essential mechanical control methods, but they aren’t 100% effective. Diatomacoues earth is lauded online, but I’ve never seen it recommended as an effective control method from any reputable source. It likely has some effect, but it’s doubtful that it will end the infestation. Lowering the relative humidity with dehumidifiers isn’t an effective control solution, because larvae seek out dark, humid areas. They develop in their own micro-habitats which have regulated micro-environments, thus temperature and RH are largely unaffected by surrounding conditions. Bathing a dog too often can be detrimental to its skin. It removes the natural oils needed for a healthy coat, and can leave the dog itchy and irritated.

      If you wish to forgo all chemical methods, I’d recommend continuing to vacuum daily. Focus on rooms where the dog spends the most time (sleeping, eating, resting). If you only have hardwood floors, target the cracks in the flooring, crevices around baseboards, or anywhere debris collects. Continue laundering pet bedding at least once weekly. For control on the dog, be diligent with a flea comb and try to remove all the fleas from its coat daily.

      To prevent fleas from accessing your bed, ensure your sheets don’t hang to ground. Fleas can’t jump higher than a human ankle, so they won’t have a route into the bed. Though, they may be jumping on you before you enter the bed.

      All stages of fleas in the car should die if exposed to temperatures above 50°C for an extended period of time. I’m not certain on the specific amount of time needed to kill the fleas, but I’d assume a couple days of the car parked outside in the sun should be enough.

      • Ani December 15, 2016, 11:17 am

        Try WONDERCIDE! All natural flea repellent chemical free. My 2 dogs and cat infested my house last year. they got fleas at a farm from the farm animals. I sprayed Wondercide on my pets, carpet,bedding, toys, etc and I was flea free. i also sprayed the dogs every 2-3 days & consitantly vacummed. I would say i was flea free within 2 weeks tops. I would still spray wondercide on my carpet once a month just for precaution. Good Luck

  • Sara October 3, 2016, 12:30 am

    Hi Adam, Because not all items can be laundered at hot temperatures I have put some things in a freezer at -19C (-2F). Do you happen to have an idea how long they should stay in the freezer to ensure that all stages of fleas are killed?
    Many thanks for this wonderfully informative and fact-based site!

    • Adam Retzer October 3, 2016, 4:24 pm

      Hello Sara. I don’t know exactly how long it will take for 100% of fleas at all stages to die at that temperature. I can’t imagine them surviving longer than five days though, the adults being the most resistant to the cold.

  • Bryan November 3, 2016, 3:03 pm

    Hi there. I recently discovered my dog had a bad flea infestation. I treated immediately with flea treatment for the dog as well as daily vacuuming and some IGR spray for the carpeting. My main question I have is that was looking to invest in a steam cleaner for the carpets that temperatures reach a little over 200 degrees F. Will that steam cleaner be sufficient with killing the eggs and left over fleas with one or two solid treatments on my carpets?

    • Adam Retzer November 5, 2016, 4:05 pm

      Steaming cleaning is more effective at removing debris from carpets. And those high temperatures will kills the immature stages. Unfortunately, it likely won’t be 100% effective, because most of the larvae live at the base of the carpets where the hot steam won’t be able to penetrate. Also, wet carpet cleaning will reduce the efficacy of the IGR treatment.

      Steaming cleaning the carpets can be useful for establishing control. However, you’ll still want to vacuum regularly. Unless the infestation is severe, it may not be worth the investment in a steam cleaner. The steps you are currently taking should bring the infestation under control.

  • Logan humphrey November 7, 2016, 10:51 pm

    Omg I have used dawn blue on my cats a bath a day for two weeks the pest man has come and spreyed 6 times I have uses bleech I have used pinsol I have now tried borax I bought 6 boxes of borax and have covered the whole house and let it sit there been hmthere for 2 days and I am STILL SEEING FLEAS please help me. Any ANY suggestions will be taken and tried

    • Adam Retzer November 9, 2016, 6:08 pm

      Please view our page on How to get rid of fleas. It contains a comprehensive guide.

      • Pam Durst November 19, 2016, 10:57 am

        Using borax takes about a month before all fleas are gone. The borax doesn’t kill the adult fleas but it dehydrates the larva as they hatch out and so the cycle is broken and lasts from 6 months to a year. I am having a problem at my house this year though, not with the fleas inside because borax is very effective, but outside, on account of a neighbor with tied up, outside dogs who are apparently breeding fleas. I now have an infestation in my backyard that I am trying to figure out. My neighbor next door has used chemicals on her dogs, and chemically treated her backyard (as her property backs up to the neighbor with the infested dogs), but she told me today that she is still having to pick fleas off of her dogs when they come into the house. I comb my cats and dogs with a flea comb a few times a day to keep the fleas from living in my house. The cats don’t go out but still get a flea or 2 from contact with the dogs. I’m in Alabama and I know that the problem is compounded by the drought that we have been experiencing for the better part of 2 months now. I’m praying for God’s deliverance from these miserable pests, while doing what I can…good luck and God Bless!

        • Gloria December 11, 2016, 8:13 pm

          I feel sorry for those tied up dogs. They should be reported

  • Crystal November 8, 2016, 7:05 am

    Hi I live in Minnesota and the winters here get well below freezing, if my cat goes out side in a daily bases and sometimes they are gone for several days, how come does my cat comes in they still have fleas on them, even if it’s below 0

    • Adam Retzer November 9, 2016, 6:06 pm

      Fleas lay their eggs on the host. The eggs aren’t sticky and fall off within a few hours. The eggs then develop in the host’s environment, indoors this is most often carpeting. In homes, they’ll mature into adults in 17 to 26 days. The newly emerged adults will then jump on the host. So, even if the cat goes outside in the cold, and the fleas die, the cat may quickly acquire fleas again upon re-entering the home.

      In addition, fleas can survive on warm-bodied hosts in the winter. The adults don’t leave the host once acquired, so they will be protected from the cold weather.

      • Kat November 14, 2016, 1:30 pm

        i have a large shag rug that i love. I put it outdoors while treating indoors for fleas. Its been outside for a while now. I now would like to bring it back inside. It is now cold and dry outside. 50s at night 65 sunny in day. How can i be sure it wont bring fleas inside? If i spray the underside with igr will it be enough? I have it hanging over in the sun currently. It is too thick to vaccuum the top. I love the rug. But im scared to bring it in? Please help. It keeps our feet warm in the kitchen. Thankyou

        • Adam Retzer November 14, 2016, 2:39 pm

          How long has the rug been outside? If the coldest it gets at night is in the 50’s, then all the fleas may not be killed. Flea larvae will avoid sunlight, so placing it in the sun is useful. However, they may just crawl deeper into the fibers. Spraying the rug with an IGR will help prevent eggs and larvae from maturing into adults. I’m not sure how effective spraying the underside will be though.

          You should be fine bringing the rug back inside. There may be fleas in it, but if the house and pets are treated, then the fleas should die soon after emerging. Allowing the fleas to emerge and then die may be one of the best ways to get rid of them, since you can’t vacuum the rug. Any new eggs falling on the rug won’t be able to develop, because of the IGR you plan on spraying (you’ll need to spray the topside of the rug, where the eggs would fall onto).

  • Chavella June 5, 2017, 1:29 pm

    I can’t get rid of my fleas! I think they’re also in my attic and duct work as well. I thought I had gotten them isolated to one bathroom but turnred on my AC unit and now they’re back all over the house. Should I pull up all my carpet or what??? They don’t seem to be dying and I’ve been fighting them for months now!!!

    • Adam Retzer June 6, 2017, 5:07 pm

      Please see our page on How to get rid of fleas. It contains a comprehensive guide. After reading it, please let me know if you still have any specific questions.

      • Rachelle August 13, 2017, 5:42 pm

        Hi Adam. We just moved on 13 acres in Western NC. The property (the ground) has a major flea infestation. When you walk they even jump on us. Help me!! I hate using heavy chemicals!! My dogs were on the ground 12 minutes and I removed 80 fleas off of them. I have them protected now but we have a lot of land with a lot of fleas!! What would you do?

        • Adam Retzer September 28, 2017, 11:30 am

          Your best bet is to use a preventative flea medication on the dog, such as flea drops or oral meds. One option is Fiproguard Plus, a generic version of Frontline Plus. You won’t be able to remove the fleas from the land, as it is a lot of land and wild animals will continually deposit new eggs. So having the your dog treated is the best way to prevent the fleas from infesting your home.

          You may also want to consider applying an insect growth regulator to your carpets. IGRs mimic natural insect hormones that regulate development. Exposed eggs are larvae won’t be able to mature. IGRs last for 7 months indoors and are good for prevention, plus they’re considered safer than traditional insecticides because they specifically target insect endocrine systems. Martin’s IGR is a good choice.

  • Betty August 12, 2017, 3:07 am

    Today my pet groomer called to say she found a couple of fleas be on my dog. I was surprised because my dog is indoors most of the day and even though she often sleeps with me, I have no bites. The groomer bathed her with a flea-fighting shampoo and gave her a Frontline plus treatment and a very short haircut.
    Needless to say, while she was gone I looked to see what I should do before she got back. I have washed, dried, and ironed sheets, pillowcases. A memento blanket that cannot be washed in hot water is now bagged and in my freezer for the next 2 weeks. I’ve washed my PJs in hot water. I also threw out the dog’s bed and favorite rug; They both were old and ratty looking anyway. I vacuumed the entire house (no carpet or rugs). My question is, is it too much to hope that 1) because of lack of bites or visible fleas, and 2)with all the measures I have taken, is it possible that I’ve seen the last of the fleas? By the way, the dog is 12 and has never had them before.

    • Adam Retzer September 29, 2017, 12:15 pm

      It sounds like you’ve taken the correct steps to resolve the problem. And it sounds like the infestation is mild. However, you’ll likely continue to see fleas here or there for around 8 weeks. This is why pet treatments are usually given for 3-4 months. Eggs, larvae, and pupae make up 95-99% of infestations. They live hidden in the environment. The sanitation procedures you’ve done should have eliminated a large portion of them, but some likely escaped your efforts. They will pop up as adults when they mature and emerge from their cocoons. This isn’t much to worry about, as it’s normal. They’ll die when they jump onto your treated dog. Or they will die when you vacuum them up.

  • Dawn August 26, 2017, 7:03 am

    I am flee spraying scrubbing everything and washing and drying in hot temps I also sprayed yard but still have flees anyone have anymore suggestions I am at my wits end

  • Don September 9, 2017, 8:46 pm

    I have hardwood floors with a few through rugs. I have washed everything including my rugs and I’ve sprayed inside and out. I vacuum everyday and I still can’t get rid of them.
    The guy next door has cats that get into my yard and in the parking lot and they have attracted 3 tomcats that are in my yard all the time. Everytime I walk outside I get bites, so I put my stuff in the oven as soon as I come home. I have been putting things in my oven on low, about 170F, for an hour or two. Is that long enough to kill fleas in my shoes and jeans etc.? I do this everytime I come home. So is 2 hours at 170F long enough to kill any fleas in my shoes and socks, etc.?

    • Adam Retzer September 29, 2017, 10:27 am

      Two hours should be long enough at that temperature to kill any fleas. However, it’s unlikely that fleas are living on those items. Usually they are just incidentally on clothes when they jump onto a person, but they don’t stay there. And laundering the clothing is probably an easier method to kill any fleas.

      If you think your yard is the source of the problem, you may want to check out our page on flea sprays for yards. It contains comprehensive information on outdoor control.

  • linda September 17, 2017, 2:47 am

    i found out my dog had adult fleas after we closed our cabin for the winter in upper pennisula michigan. we turn heat off for winter. can adult fleas survive without host on below freezing temps?

    • Adam Retzer September 29, 2017, 10:41 am

      If the home reaches sub-freezing temperatures, then the fleas won’t be able to survive. The majority will die within 24 hours in sub-freezing temperatures. All will be dead by 10 days.

      • Rachael October 4, 2017, 7:46 pm

        So if I allow my house to get to sub freezing temperatures in the winter for 10 days, will this kill all fleas in my house in all stages??? What temperatures exactly should it be between to do this and will it kill the eggs and larvae in the carpet and hardwood floors?

        • Adam Retzer October 5, 2017, 11:29 am

          I am not sure exactly how long it will take. The article contains the most precise information I have. Generally it’s not a good control technique to try to alter indoor climates. Fleas develop in protected micro-habitats that have their own micro-climate (e.g. deep within carpets), which is keep fairly regulated and isn’t drastically affected by surrounding conditions. Exceptions may be cars that are left outside in the winter, or cabins residing in really cold areas.

  • Karen September 19, 2017, 7:23 am

    Any way to get estimate? Live in 3 bedroom ranch. No basemennt. Small house. Husband and i both on disability.

    • Adam Retzer September 29, 2017, 10:58 am

      A price estimate for extermination? I am not sure. This site is just dedicated to providing well-researched information, we aren’t a pest control service company.

  • Cheri September 22, 2017, 1:36 pm

    I accidentally bought home bed bugs when I purchased a used piece of furniture from an unscrupulous person. I’m in the process of having my house heated to eradicate the problem, but have seen my dogs itching a little bit from fleas. I continuously treat them for fleas, but wondered if the heat eradication might take care of any stragglers in the house. Thanks

    • Adam Retzer September 29, 2017, 12:47 pm

      Trying to alter the climate within homes to kill fleas isn’t a very effective technique. This is because the eggs, larvae, and pupae live deep within carpets or other refuges. These micro-habitats have their own regulated micro-climate that is mostly unaffected by the surrounding conditions of the room.

  • Becca October 26, 2017, 7:21 am

    Our dogs sleep with my daughter and were recently at the vet where he found “flea dirt” on them. I have yet to see an actual flea. They have been treated with Frontline gold and I am doing all carpets with a chemical treatment. My question is how to treat my daughters bedding as safe and effectively as possible? She has a lot of stuffed animals on the bed too?

    • Adam Retzer October 26, 2017, 2:34 pm

      Adult fleas live permanently on their animal host once it is acquired. Eggs are laid on the host, but they aren’t sticky and fall off within a few hours. So, if there are fleas developing on the bed, then they are on the surface of the sheets, or folds within the fabrics. Fleas don’t infest mattresses. Laundering the bedding is sufficient to kill any fleas on beds.

      There probably aren’t any fleas on the stuffed animals, but it is possible if the dog laid on them. Eggs and larvae would have a hard time attaching to these items, so vigorously shaking them should remove most of the potential fleas. Some people will put items like plush toys in a bag, and then put the bag in a freezer for around 5 days. Putting them in the dryer (if it is safe for the items) should also kill any fleas.

  • Amity Frazer November 21, 2017, 10:08 am

    I have a ton of blankets and pillows I can’t launder in one day…. Can I lay then outside where the temps are below 45° now for a period of time to kill the fleas? I can do the spraying and such on the carpets and furniture I can’t lay outside.

    • Adam Retzer November 28, 2017, 10:15 am

      Leaving the items outside in the cold should kill any flea stages. However, it may take a while (a few weeks) at 45°F. In subfreezing temperatures, 100% should die within 5 days.

  • Vashti Campbell November 29, 2017, 9:58 am

    Hi. I read that sprinkling salt and baking soda on carpets not only helps to freshen carpets but works it’s way into the carpet fibres and dehydrates flea eggs, so this is what I do. Do you think this works?

    • Adam Retzer November 29, 2017, 4:54 pm

      I’ve read about similar control measures online, but I think the authors of those articles are just pandering to people’s desires for natural remedies, without concerning themselves with what actually works. I’ve never read anything in the science literature stating that salt or baking soda will control a flea infestation. That said, there are many anecdotal reports of pet-owners claiming that these methods work. Perhaps more research needs to be done.

  • Rob December 2, 2017, 7:50 am

    I don’t see any mention of using foggers to treat entire rooms or spaces. What do you think of their effectiveness? Also, what are the health concerns for people and pets (after, of course, the specified time has passed and the room is again aired out)? Thanks!

    • Adam Retzer December 4, 2017, 10:03 am

      Hello Rob, I’ve written a page on this here: Best flea foggers. Foggers aren’t as effective as sprays you can apply directly into flea habitats. And the mist gets on more surfaces, which can lead to more safety concerns. The page I’ve linked covers all of this.

  • Vashti Campbell December 8, 2017, 1:21 am

    Hi. I keep reading that to get rid of fleas , the washing machine should be set at the hottest temperature of 90 degrees? Seriously!? This can’t be right!? My electricity bill would be sky high if I did all washes at that temperature.

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