Like all insects, mosquitos are cold-blooded creatures which means that they are incapable of regulating their body heat. This means that their body temperature is essentially the same as their surroundings. Mosquitoes actually function best when at 80 degrees F, and tend to become lethargic at 60 degrees F, they actually cannot function below 50 degrees F. If you live or visit tropical areas then be expected to see mosquitoes active all year round. If you are in a more temperate climate then 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 will 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.