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:
Southeast
- Alabama
- Florida
- Georgia
- North Carolina
- South Carolina
- Virginia
South
- Arkansas
- Kansas
- Louisiana
- Mississippi
- Oklahoma
- Texas
Ohio Valley
- Illinois
- Indiana
- Kentucky
- Missouri
- Ohio
- Tennessee
- West Virginia
West
- California
- Nevada
Northeast
- 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:
- DEET
- Picaridin
- IR3535
- Oil of lemon eucalyptus (OLE)
- Para-menthane-diol (PMD)
- 2-undecanone
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.
- Use screens on doors and windows.
- If outside, a simple electric fan can help keep mosquitoes away, as they are very weak flyers.
- Stop mosquitoes from laying eggs in water by emptying items that hold water, such as tires, buckets, planters, toys, pools, birdbaths, and trash containers. Do this about once a week.
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.