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

Mosquito months in Cleveland County

In a normal year mosquito season in Cleveland County, OK starts around March 23 and ends around November 12, 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 Cleveland County, and when

• Start tipping out standing water weekly by March 9.
• Book any yard treatment for late March, ahead of the July peak.
• Repellent can go away after November 12.
• 27 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to September, and check OK spray notices.

Cleveland County against the rest of OK

Cleveland County has the 32nd longest season of 77 OK counties, at 234 days against 271 in Choctaw County and 193 in Cimarron County. Its mean temperature is 60.9°F.

• Jackson County: March 22 to November 12 (235 days, 7 WNV)
• Roger Mills County: March 22 to November 11 (234 days, 1 WNV)
• Logan County: March 23 to November 11 (233 days, 1 WNV)
• McClain County: March 23 to November 11 (233 days, 0 WNV)

West Nile in Cleveland County

From 1999 to 2025, CDC ArboNET counted 56 human West Nile cases in Cleveland County (36 neuroinvasive) across 12 years. The worst was 2024 with 10; the latest was 2025.

See how the dates are worked out, and reading the West Nile counts.