Mosquito season in St. Johns County, FL: when it starts and ends

Mosquito months in St. Johns County

In a normal year mosquito season in St. Johns County, FL starts around January 25 and ends around January 10, about 50 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 St. Johns County, and when

• Start tipping out standing water weekly by January 11.
• Book any yard treatment for late January, ahead of the July peak.
• Repellent can go away after January 10.
• 2 West Nile cases since 2016 (last 2023): you should use repellent at dusk May to October, more so if over 60.

St. Johns County against the rest of FL

St. Johns County has the 29th longest season of 67 FL counties, at 350 days against 365 in Broward County and 281 in Gilchrist County. Its mean temperature is 70.6°F.

• Hardee County: January 28 to January 15 (352 days, 0 WNV)
• Hernando County: January 24 to January 9 (350 days, 0 WNV)
• DeSoto County: January 28 to January 11 (348 days, 0 WNV)
• Bay County: January 23 to January 5 (347 days, 10 WNV)

West Nile in St. Johns County

From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in St. Johns County (3 neuroinvasive) across 3 years. The worst was 2023 with 1; the latest was 2023.

More: how the dates are worked out · where mosquitoes never stop.