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

Mosquito months in Seminole County

In a normal year mosquito season in Seminole County, OK starts around March 24 and ends around November 9, about 33 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 Seminole County, and when

• Start tipping out standing water weekly by March 10.
• Book any yard treatment for late March, ahead of the July peak.
• Repellent can go away after November 9.
• 2 West Nile cases since 2016 (last 2023): you should use repellent at dusk June to September, more so if over 60.

Seminole County against the rest of OK

Seminole County has the 41st longest season of 77 OK counties, at 230 days against 271 in Choctaw County and 193 in Cimarron County. Its mean temperature is 61°F.

• Mayes County: March 23 to November 8 (230 days, 1 WNV)
• Garvin County: March 24 to November 9 (230 days, 3 WNV)
• Caddo County: March 25 to November 10 (230 days, 2 WNV)
• Major County: March 26 to November 10 (229 days, 3 WNV)

West Nile in Seminole County

From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in Seminole County (5 neuroinvasive) across 5 years. The worst was 2012 with 2; the latest was 2023.

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