Mosquitoes, like all insects, are cold-blooded creatures. As a result, they are incapable of regulating body heat and their temperature is essentially the same as their surroundings. Mosquitoes function best at 80 degrees F, become lethargic at 60 degrees F, and cannot function below 50 degrees F. In tropical areas, mosquitoes are active year round. In temperate climates, adult mosquitoes of some species become inactive with the onset of cool weather and enter hibernation to live through the winter.
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 (these are the mosquitoes one might see on a warm January or February day).
In spring, the females emerge from hibernation, blood feed and lay the eggs that produce the next generation of adults. A limited number of mosquitoes overwinter in the larval stage, often buried in the mud of freshwater swamps. When temperatures rise in spring, these mosquitoes begin feeding, complete their immature growth and eventually emerge as adults to continue their kind.