Mosquito season in Knox County, TX: when it starts and ends

Mosquito months in Knox County

In a normal year mosquito season in Knox County, TX starts around March 11 and ends around November 21, 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 Knox 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 21.
• 1 West Nile case since 2016 (last 2016): you should use repellent at dusk May to September, more so if over 60.

Knox County against the rest of TX

Knox County has the 167th longest season of 254 TX counties, at 255 days against 365 in Cameron County and 191 in Lipscomb County. Its mean temperature is 64.3°F.

• Hood County: March 10 to November 20 (255 days, 13 WNV)
• Scurry County: March 10 to November 20 (255 days, 0 WNV)
• Wilbarger County: March 9 to November 18 (254 days, 2 WNV)
• Borden County: March 10 to November 19 (254 days, 0 WNV)

West Nile in Knox County

From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in Knox County (3 neuroinvasive) across 3 years. The worst was 2016 with 1; the latest was 2016.

See how the dates are worked out, and when mosquitoes go away for the winter.