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

Mosquito months in Gwinnett County

In a normal year mosquito season in Gwinnett County, GA starts around March 12 and ends around November 22, about 36 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 Gwinnett County, and when

• Start tipping out standing water weekly by February 26.
• Book any yard treatment for mid March, ahead of the July peak.
• Repellent can go away after November 22.
• 7 West Nile cases since 2016 (last 2025): you should use repellent at dusk June to September, more so if over 60.

Gwinnett County against the rest of GA

Gwinnett County has the 106th longest season of 159 GA counties, at 255 days against 347 in Glynn County and 199 in Union County. Its mean temperature is 61.1°F.

• Taliaferro County: March 12 to November 23 (256 days, 0 WNV)
• DeKalb County: March 12 to November 22 (255 days, 28 WNV)
• Chattahoochee County: March 11 to November 20 (254 days, 0 WNV)
• Glascock County: March 13 to November 22 (254 days, 0 WNV)

West Nile in Gwinnett County

From 1999 to 2025, CDC ArboNET counted 19 human West Nile cases in Gwinnett County (10 neuroinvasive) across 11 years. The worst was 2012 with 5; the latest was 2025.

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