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. However, not all fleas die. 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.

  • 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).

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