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

Mosquito months in Sherman County

In a normal year mosquito season in Sherman County, TX starts around April 10 and ends around October 30, about 29 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 Sherman County, and when

• Start tipping out standing water weekly by March 27.
• Book any yard treatment for early April, ahead of the July peak.
• Repellent can go away after October 30.
• No West Nile cases since 2016, so bites in Sherman County are a nuisance; check window screens.

Sherman County against the rest of TX

Sherman County has the 250th longest season of 254 TX counties, at 203 days against 365 in Cameron County and 191 in Lipscomb County. Its mean temperature is 56.5°F.

• Hansford County: April 10 to November 1 (205 days, 4 WNV)
• Parmer County: April 11 to November 2 (205 days, 4 WNV)
• Hartley County: April 11 to October 31 (203 days, 1 WNV)
• Bailey County: April 12 to October 30 (201 days, 2 WNV)

West Nile in Sherman County

From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Sherman County (4 neuroinvasive) across 4 years. The worst was 2004 with 2; the latest was 2015.

Background: when mosquitoes go away for the winter; how the dates are worked out.