Are Mosquitoes Getting Worse?

Experts warn that they might be getting even worse. Mosquito activity depends on several factors, such as temperature, relative humidity, and precipitation. When these variables remain in the ideal range for mosquitos for an especially long time throughout the year—as they have in recent years—the mosquito season is prolonged, and local populations often explode.

Longer Mosquito Seasons

Studies have shown that mosquito season is getting longer, affording the insects more time to reproduce.

One analysis by Climate Central assessed long-term trends in mosquito days across the US. A mosquito day, as it is defined here, is a day with a relative humidity of 42% or higher, and daily minimum and maximum temperatures between 50—95℉.

It found that, from 1979 to 2022, 173 locations (out of 242—71%) experienced an increase in annual mosquito days—by about 16 days, on average.

Regions with the Most Mosquito Days


According to the National Centers for Environmental Information, there are nine climatically consistent regions within the contiguous United States. The regions are defined below:


  • Alabama
  • Florida
  • Georgia
  • North Carolina
  • South Carolina 
  • Virginia 


  • Arkansas 
  • Kansas
  • Louisiana
  • Mississippi
  • Oklahoma
  • Texas

Ohio Valley

  • Illinois
  • Indiana
  • Kentucky
  • Missouri
  • Ohio
  • Tennessee
  • West Virginia


  • California
  • Nevada


  • Connecticut 
  • Delaware
  • Maine
  • Maryland 
  • Massachusetts 
  • New Hampshire 
  • New Jersey
  • New York 
  • Pennsylvania
  • Rhode Island
  • Vermont 

Upper Midwest

  • Iowa
  • Michigan
  • Minnesota
  • Wisconsin

The south has the most annual mosquito days.

The Ohio Valley and Northeast saw the biggest region-wide increases in mosquito days since 1979.

Mosquitoes Are Worse in Cities

Mosquitoes flourish in urban habitats. They breed best in rainwater collected in human made containers, like garden embellishments, bits of trash such as empty cans, flowerpots, and rainwater-collecting systems. The continual expansion of urban environments, coupled with ever-increasing mosquito days, is a boon to mosquito populations.

Cities that Experienced Highest Increase in Mosquito Days, 1979-2020


More Mosquito Days Are a Problem

The increasing number of mosquito days in the US creates the perfect conditions for mosquitoes to start reproducing earlier and for longer periods of time. This is significant, since while they might not look like much, mosquitoes kill more people than any other creature in the world. They do this by spreading a wide range of diseases, such as malaria, dengue, West Nile, yellow fever, Zika, chikungunya, and lymphatic filariasis. Even in areas where mosquitoes seldom carry deadly diseases, they are the definitive nuisance, causing intensely itchy bites and all-around unpleasantness.

How to Protect Yourself on a Mosquito Day

Use Insect Repellant. The following insect repellants are EPA registered, and have been proven safe and effective:

Wear loose-fitting, long-sleeved shirts and pants. You can also treat your clothing with 0.5% permethrin, for added protection. Permethrin should not be applied directly to skin, however.

Take steps to control mosquitoes inside and outside.

Get Mosquito Control for the Yard

Mosquito treatment is a quick and easy way to eliminate mosquitoes on your property. At MissQuito, our all-female team of trained experts target mosquitos throughout their entire lifecycle using a variety of eco-friendly repellants. With same to next day appointments, and the ability to work around your schedule, our mosquito control is as convenient as it is effective.

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