Mosquito season in Johnson County, TN: when it starts and ends

Mosquito months in Johnson County

In a normal year mosquito season in Johnson County, TN starts around April 12 and ends around October 24, about 28 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 Johnson County, and when

• Start tipping out standing water weekly by March 29.
• Book any yard treatment for mid April, ahead of the July peak.
• Repellent can go away after October 24.
• No West Nile cases since 2016, so bites in Johnson County are a nuisance; check window screens.

Johnson County against the rest of TN

Johnson County has the 94th longest season of 95 TN counties, at 195 days against 252 in Hamilton County and 186 in Carter County. Its mean temperature is 53.1°F.

• Claiborne County: April 10 to October 28 (201 days, 0 WNV)
• Grainger County: April 11 to October 27 (199 days, 0 WNV)
• Carter County: April 20 to October 23 (186 days, 0 WNV)

West Nile in Johnson County

From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Johnson County (1 neuroinvasive) across 2 years. The worst was 2003 with 1; the latest was 2003.

Background: when the season starts across the US; how the dates are worked out.