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

Mosquito months in Marion County

In a normal year mosquito season in Marion County, TX starts around March 3 and ends around November 22, about 38 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 Marion County, and when

• Start tipping out standing water weekly by February 17.
• Book any yard treatment for early March, ahead of the July peak.
• Repellent can go away after November 22.
• No West Nile cases since 2016, so bites in Marion County are a nuisance; check window screens.

Marion County against the rest of TX

Marion County has the 134th longest season of 254 TX counties, at 264 days against 365 in Cameron County and 191 in Lipscomb County. Its mean temperature is 64.7°F.

• Leon County: March 6 to November 26 (265 days, 0 WNV)
• Rains County: March 6 to November 26 (265 days, 1 WNV)
• Cooke County: March 5 to November 24 (264 days, 8 WNV)
• Harrison County: March 5 to November 24 (264 days, 3 WNV)

West Nile in Marion County

CDC ArboNET lists no human West Nile cases for Marion County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 1 of those years.

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