Mature fleas, eggs, larvae and pupae die after being exposed to temperatures of 37 degrees Fahrenheit and below. Fleas can withstand these temperatures for days until finally dying.
Fleas do not die overnight when temperatures drop to near-freezing. A flea can take up to 10 days of consistently cold weather hitting below 37 degrees to die. If temperatures rise above 37 degrees within the 10-day period, fleas are capable of warming up enough to survive through the previously freezing temperatures. It is only when fleas are exposed to consistent near-freezing weather that they die.
Though fleas can die from low temperatures, some may find alternative solutions to stay warm. Fleas may seek body heat by living on wild animals such as raccoons or find shelter in garages, barns, under decks or in outdoor pet bedding.