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

Mosquito months in Hamilton County

In a normal year mosquito season in Hamilton County, TN starts around March 11 and ends around November 18, 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 Hamilton County, and when

• Start tipping out standing water weekly by February 25.
• Book any yard treatment for mid March, ahead of the July peak.
• Repellent can go away after November 18.
• 6 West Nile cases since 2016 (last 2018): you should use repellent at dusk June to September, more so if over 60.

Hamilton County against the rest of TN

Hamilton County has the 1st longest season of 95 TN counties, at 252 days against 252 in Hamilton County and 186 in Carter County. Its mean temperature is 61.3°F.

• Sequatchie County: March 12 to November 15 (248 days, 0 WNV)
• Shelby County: March 15 to November 17 (247 days, 47 WNV)

West Nile in Hamilton County

From 1999 to 2025, CDC ArboNET counted 13 human West Nile cases in Hamilton County (13 neuroinvasive) across 7 years. The worst was 2017 with 4; the latest was 2018.

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