Mosquito season in Harper County, OK: when it starts and ends
Mosquito months in Harper County
In a normal year mosquito season in Harper County, OK starts around April 7 and ends around November 1, about 30 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Harper County, and when
- Start tipping out standing water weekly by March 24.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after November 1.
- 3 West Nile cases since 2016 (last 2023): you should use repellent at dusk June to September, more so if over 60.
Harper County against the rest of OK
Harper County has the 73rd longest season of 77 OK counties, at 208 days against 271 in Choctaw County and 193 in Cimarron County. Its mean temperature is 58°F.
- Ellis County: April 5 to November 4 (213 days, 2 WNV)
- Delaware County: April 3 to October 30 (210 days, 1 WNV)
- Texas County: April 8 to November 1 (207 days, 4 WNV)
- Dewey County: April 8 to October 29 (204 days, 1 WNV)
West Nile in Harper County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Harper County (1 neuroinvasive) across 2 years. The worst was 2023 with 3; the latest was 2023.
See how the dates are worked out, and when mosquitoes go away for the winter.