2021 Mosquito Forecast for the Southeast In 2021, it’s expected that these mosquito populations will be average or slightly above average. This is due to a wetter-than-normal outlook for the summer as well as temperatures that will be average or slightly above average, according to the National Weather Service. Mosquito season will start around mid-February to early April, depending how far north your state is in the region. For example, South Florida’s mosquito season will h