At what temperature do fleas die?

Fleas will die when the temperature reaches or falls below 37 F. However, the temperature has to remain at or below that point for as long as 10 consecutive days for the fleas to freeze to death. If the temperature climbs above 37 during that time period, the fleas often get warm enough to survive longer.

Fleas are cunning enough to discover ways to keep from freezing when it is cold outside. Some of them will find a wild animal to serve as a host, while others will burrow into warm spots in garages, barns or other outdoor structures to wait out the cold weather.