Mosquito season in Major County, OK: when it starts and ends
Mosquito months in Major County
In a normal year mosquito season in Major County, OK starts around March 26 and ends around November 10, about 33 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Major County, and when
- Start tipping out standing water weekly by March 12.
- Book any yard treatment for late March, ahead of the July peak.
- Repellent can go away after November 10.
- 3 West Nile cases since 2016 (last 2025): you should use repellent at dusk June to September, more so if over 60.
Major County against the rest of OK
Major County has the 43rd longest season of 77 OK counties, at 229 days against 271 in Choctaw County and 193 in Cimarron County. Its mean temperature is 59.9°F.
- Seminole County: March 24 to November 9 (230 days, 2 WNV)
- Caddo County: March 25 to November 10 (230 days, 2 WNV)
- Nowata County: March 26 to November 10 (229 days, 0 WNV)
- Grady County: March 25 to November 8 (228 days, 1 WNV)
West Nile in Major County
From 1999 to 2025, CDC ArboNET counted 4 human West Nile cases in Major County (3 neuroinvasive) across 4 years. The worst was 2025 with 1; the latest was 2025.
More: how the dates are worked out · when the season starts across the US.