What Temperature Kills Fleas? Your Guide to Beating These Pests

Fleas are tiny and bloodsucking insects that can become a persistent nightmare in any household. These parasites thrive in warm and humid environments, making them particularly prevalent during the summer months. However, temperature plays a crucial role in their survival. Fleas cannot withstand extreme temperatures, whether it’s scorching heat or freezing cold. 

When exposed to high temperatures, fleas become dehydrated and eventually die off. This makes methods like steam cleaning, hot water washing, or even leaving infested items out in the sun effective in killing fleas and their eggs. Conversely, extreme cold can also be utilized to eliminate fleas. Freezing temperatures can cause fleas to enter a dormant state or even kill them outright. 

Understanding how temperature affects these pests is key to effectively combating infestations, which will be explained in this article.

What Temperature Kills Fleas? Your Guide to Beating These Pests
What Temperature Kills Fleas? Your Guide to Beating These Pests

How Freezing Temperatures Kill Fleas

Adult fleas cannot survive temperatures below 32°F (0°C). This icy blast proves fatal within a few days. However, their younger counterparts, the eggs and larvae, are slightly more resilient to the cold. While they are still affected by freezing conditions, they may require sustained exposure to lower temperatures to ensure complete eradication. 

This discrepancy underscores the importance of sustained below-freezing temperatures in flea elimination efforts. Merely experiencing one cold night may not be sufficient to eradicate all life stages of fleas. They can survive for a while at temperatures as low as 55.4°F (13°C), though prolonged exposure to this coolness will eventually disrupt the life cycle of fleas and prevent reinfestation.

Flea vs Freezing
Flea vs Freezing

Can Fleas Survive Winter Outdoors?

Fleas can survive winter outdoors under certain conditions. They can hibernate in protected outdoor areas such as animal burrows, leaf litter, or under the cover of vegetation. However, sustained periods of freezing temperatures can significantly reduce flea populations outdoors. During harsh winter conditions, many fleas may die off, and the development of flea life stages may slow down. 

Some fleas may still survive by seeking shelter in warmer microenvironments until conditions become more favorable for their activity and reproduction. Therefore, while winter weather may suppress flea populations outdoors, it may not completely eliminate them.

Fleas can survive winter outdoors under certain conditions
Fleas can survive winter outdoors under certain conditions

Using Cold Strategically

While extreme cold temperatures can be a strong weapon against fleas, here are some other cold strategies to limit their populations:

  • Freezing items: Small, washable items such as pet bedding, toys, and clothing can be effectively treated for flea control by placing them in the freezer. Freezing these items for a period of 24 to 48 hours can kill fleas and their eggs, helping to break the flea life cycle.
  • Outdoor Prevention: During colder months, outdoor temperatures naturally drop, which can help suppress flea populations in outdoor environments. This can be beneficial for pet owners who let their pets spend time outdoors, as the cold weather can help reduce the risk of flea infestations in the yard or garden.
  • Winter Weather: In regions with harsh winters, sustained periods of freezing temperatures can significantly reduce flea populations in outdoor environments. While fleas may seek refuge in warmer areas like animal burrows or outdoor structures, the overall flea activity tends to decrease during colder months.
  • Preemptive Measures: Taking preemptive measures before flea season begins can help prevent infestations from occurring in the first place. This may include treating pets with veterinarian-recommended flea prevention products, maintaining a clean living environment through regular vacuuming and cleaning, and implementing outdoor flea control measures such as landscaping and pest management.
Using cold strategies
Using cold strategies

How Temperatures Can Kill Fleas

Fleas are highly sensitive to temperature, with their survival significantly impacted by extremes in heat. Generally, fleas cannot survive temperatures above 95°F (35°C). At these elevated temperatures, fleas become stressed, dehydrated, and ultimately perish. 

However, the relationship between temperature and flea survival is intricately linked to relative humidity. High humidity levels can mitigate the lethal effects of heat on fleas by providing moisture, allowing them to endure slightly higher temperatures. Conversely, low humidity exacerbates the lethal effects of heat, making fleas more susceptible to temperature-induced mortality. 

Therefore, while elevated temperatures are detrimental to flea survival, the presence of adequate humidity can influence their resilience, highlighting the importance of considering both factors in effective flea control strategies.

Fleas are highly sensitive to temperature
Fleas are highly sensitive to temperature

Practical Applications of Heat

When tackling flea infestations, washing bedding with hot water is a crucial step in eliminating these pests. Hot water effectively kills fleas and their eggs, helping to break the flea life cycle. For optimal results, use the hottest water setting recommended for the fabric. Remember to check care labels before washing any items in hot water.

In addition to washing, drying infested items in high-heat dryer cycles can serve as a powerful tool for flea control. The high temperatures achieved in the dryer effectively kill fleas, larvae, and eggs. However, it’s important to note any fabric limitations to prevent damage. Delicate fabrics may be susceptible to heat damage, so be sure to follow care instructions and use lower heat settings if necessary.

Steam cleaning is another highly effective method for eliminating fleas from carpets and upholstery. Steam cleaners produce temperatures upwards of 200°F (93°C) or higher, which is lethal to fleas at all life stages. The intense heat generated by steam penetrates deep into fabrics and carpets, killing fleas and their eggs on contact. Additionally, steam cleaning doesn’t require the use of harsh chemicals, making it a safe and eco-friendly option for flea control. Its ability to reach into crevices and tight spaces makes it particularly effective in thoroughly treating infested areas, ultimately helping to rid your home of fleas more efficiently.

Washing bedding with hot water is a crucial step in eliminating these pests
Washing bedding with hot water is a crucial step in eliminating these pests

Controlling Fleas By The Other Methods 

While extreme temperatures, both hot and cold, can be valuable weapons in controlling flea populations, they are typically just one aspect of a comprehensive flea control plan. Fleas have a complex life cycle, and a successful eradication strategy requires a multi-pronged approach. Here are some additional key elements for flea control:

  • Treat Your Pets: This is absolutely crucial. Regular flea medication on your furry companions disrupts the flea life cycle and prevents them from becoming breeding grounds for these itchy invaders. Consult your veterinarian to choose the most appropriate flea treatment for your pet.
  • Vacuum Thoroughly: Vacuuming carpets, furniture, and baseboards regularly helps remove adult fleas, eggs, and larvae. Remember to empty the vacuum cleaner bag or canister outside immediately after use to prevent flea escape.
  • Professional Help in Severe Cases: For severe infestations, professional pest control services might be necessary. They have access to stronger flea control products and can ensure a more comprehensive treatment of your entire home.
Vacuuming carpets, furniture, and baseboards regularly helps remove fleas
Vacuuming carpets, furniture, and baseboards regularly helps remove fleas


Understanding the vulnerabilities of fleas to temperature variations empowers homeowners to implement more effective control strategies. By knowing that extreme temperatures can disrupt the life cycle of fleas and hinder their survival, individuals can strategically incorporate heat and cold treatments into their flea control efforts. However, remember that factors like humidity and flea life cycle stages can influence their heat and cold tolerance.

By incorporating this knowledge of flea temperature sensitivity into your overall flea control plan, you can achieve more strategic approaches. One of which is using flea preventative medications such as Bravecto or Advocate which can be found at Anipet Shop. Moreover, regular grooming of pets, thorough cleaning of living spaces, and seeking professional assistance when needed become possible to create a flea-free environment within the home.


Will washing at 40 degrees kill fleas?

Washing at 40 degrees Celsius (104 degrees Fahrenheit) might kill some fleas, but it’s not guaranteed. Fleas and their eggs are more susceptible to hotter water. While the heat of the water may kill some fleas, others may survive. To effectively eliminate fleas from items, it’s recommended to use hot water above 50 degrees Celsius or to combine washing with other flea control methods, such as vacuuming and using flea treatments.

What temperature kills fleas instantly?

Fleas are sensitive to extreme temperatures, and temperatures above 95 degrees Fahrenheit (35 degrees Celsius) can kill fleas and their eggs. However, it’s essential to note that reaching such high temperatures in everyday environments, such as washing machines or dryers, may not be feasible. Instead, using products specifically designed to kill fleas, such as insecticides or flea control treatments, is more practical for eliminating fleas effectively.

Do fleas die in winter?

Fleas can survive in colder temperatures, including winter, although their activity may decrease. While cold temperatures can slow down flea development and activity, they are not necessarily lethal to fleas unless the temperatures drop significantly below freezing for an extended period. In warmer climates, fleas may remain active throughout the year, while in colder regions, their activity may decrease but not necessarily cease entirely.

At what temperature do fleas become less active?

Fleas become less active at temperatures below 70 degrees Fahrenheit (21 degrees Celsius) and begin to die if the temperature drops below 46 degrees, or rises above 96 degrees Fahrenheit. As temperatures decrease, flea activity slows down, and their reproduction rates may decrease. However, fleas can still survive and remain active in cooler environments, particularly indoors where temperatures are more stable. Effective flea control involves a combination of environmental management, such as regular vacuuming and washing, along with appropriate flea treatments for pets.

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Lily Watson is an author specializing in veterinary care in Australia. With a profound passion for animal welfare and a solid foundation in veterinary science, Lily has dedicated herself to disseminating valuable knowledge and information for both pet owners and professionals in this field.