Mosquito Days

Climate Central's analysis of 242 U.S. locations from 1979 to 2022 shows that 71% of these sites experienced an increase in annual mosquito days, averaging a rise of 16 days. The Southeast and South currently have the highest number of mosquito days, while the Ohio Valley and Northeast saw the largest region-wide increases. The report links these trends to warming spring and fall temperatures and discusses the expanding risk of mosquito-borne diseases, such as West Nile virus and dengue, as suitable habitats shift northward and the season length for transmission increases.

• Between 1979 and 2022, 173 out of 242 analyzed locations (71%) in the contiguous U.S. saw an increase in annual mosquito days, with an average increase of 16 days.
• The Southeast and South regions experience the highest volume of mosquito days, with the Southeast averaging 218 days (60% of the year) and the South averaging 184 days (50% of the year).
• The Ohio Valley and Northeast regions experienced the most significant region-wide increases in mosquito days since 1979; 60% of the 55 locations that saw an increase of 21 days or more were located in these two regions.
• Warming trends are expanding the risk of mosquito-borne diseases: West Nile neuroinvasive disease cases in the contiguous U.S. could approximately double by 2050 compared to 1995 levels, and the potential for Aedes aegypti to transmit dengue is projected to expand into temperate North America.
• The range of disease-carrying Aedes species is projected to expand from the South and Southeast into the Ohio Valley, Upper Midwest, and up the East Coast by 2050, potentially putting tens of millions more people in the U.S. and Canada at risk.

APA

Climate Central (2023). Mosquito Days. https://www.climatecentral.org/climate-matters/mosquito-days-2023

Chicago

Climate Central. Mosquito Days. 2023. https://www.climatecentral.org/climate-matters/mosquito-days-2023.

Wikipedia

{{cite report |author=Climate Central |title=Mosquito Days |date=17 May 2023 |url=https://www.climatecentral.org/climate-matters/mosquito-days-2023 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2023mosquito, author = {{Climate Central}}, title = {{Mosquito Days}}, institution = {Climate Central}, year = {2023}, month = may, url = {https://www.climatecentral.org/climate-matters/mosquito-days-2023}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }