Mosquito season in Polk County, FL: when it starts and ends

Mosquito months in Polk County

Mosquitoes in Polk County, FL can be active in any month. The worst stretch is April to October.

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 Polk County, and when

• No off-season here: tip out standing water every week, all year.
• A yard treatment matters most April to October.
• No West Nile cases since 2016, so bites in Polk County are a nuisance; check window screens.

Polk County against the rest of FL

Polk County has the 13th longest season of 67 FL counties, at 365 days against 365 in Broward County and 281 in Gilchrist County. Its mean temperature is 74.2°F.

• Orange County: all year (365 days, 0 WNV)
• Pinellas County: all year (365 days, 1 WNV)
• St. Lucie County: all year (365 days, 0 WNV)
• Seminole County: January 14 to January 11 (362 days, 1 WNV)

West Nile in Polk County

From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in Polk County (1 neuroinvasive) across 3 years. The worst was 2014 with 1; the latest was 2014.

Background: where mosquitoes never stop; how the dates are worked out.