Mosquito season in Marshall County, OK: when it starts and ends

Mosquito months in Marshall County

In a normal year mosquito season in Marshall County, OK starts around March 11 and ends around November 19, 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 Marshall 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 19.
• 2 West Nile cases since 2016 (last 2017): you should use repellent at dusk May to September, more so if over 60.

Marshall County against the rest of OK

Marshall County has the 6th longest season of 77 OK counties, at 253 days against 271 in Choctaw County and 193 in Cimarron County. Its mean temperature is 63°F.

• Tillman County: March 11 to November 21 (255 days, 0 WNV)
• Okfuskee County: March 11 to November 20 (254 days, 1 WNV)
• Haskell County: March 9 to November 16 (252 days, 0 WNV)
• Comanche County: March 11 to November 16 (250 days, 8 WNV)

West Nile in Marshall County

From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Marshall County (0 neuroinvasive) across 5 years. The worst was 2012 with 2; the latest was 2017.

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