Mosquitoes cannot survive cold weather, and they become inactive or die off when the temperature drops below a certain point. According to WebMD, the temperature at which mosquitoes can no longer function is around 50 degrees Fahrenheit. When the temperatures dip below 60 degrees, mosquitoes can grow lethargic, and when the average temperatures hover around 50 degrees, they will go dormant or die off. A hard or killing frost, which is defined as two consecutive hours at a temperature below 28 degrees Fahrenheit, will kill virtually all exposed mosquitoes. However, not all mosquitoes die in the winter, and some species have adapted to cold weather. For example, some kinds of mosquitoes have winter-hardy eggs and hibernate as embryos in eggs laid by the last generation of females in late summer. The eggs are usually submerged under ice and hatch in spring when water temperatures rise. Other kinds of mosquitoes overwinter as adult females that mate in the fall, enter hibernation in animal burrows, hollow logs, or basements, and pass the winter in a state of torpor.