Mosquito season in Chatham County, GA: when it starts and ends

Mosquito months in Chatham County

In a normal year mosquito season in Chatham County, GA starts around February 13 and ends around December 22, about 45 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Chatham County, and when

• Start tipping out standing water weekly by January 30.
• Book any yard treatment for mid February, ahead of the July peak.
• Repellent can go away after December 22.
• 7 West Nile cases since 2016 (last 2025): you should use repellent at dusk May to September, more so if over 60.

Chatham County against the rest of GA

Chatham County has the 24th longest season of 159 GA counties, at 312 days against 347 in Glynn County and 199 in Union County. Its mean temperature is 67.5°F.

• Jeff Davis County: February 24 to January 3 (313 days, 2 WNV)
• Bryan County: February 13 to December 22 (312 days, 1 WNV)
• Wheeler County: February 24 to January 2 (312 days, 1 WNV)
• Mitchell County: February 25 to January 3 (312 days, 3 WNV)

West Nile in Chatham County

From 1999 to 2025, CDC ArboNET counted 28 human West Nile cases in Chatham County (22 neuroinvasive) across 9 years. The worst was 2011 with 10; the latest was 2025.

See how the dates are worked out, and reading the West Nile counts.