Mosquito season in McLean County, ND: when it starts and ends
Mosquito months in McLean County
In a normal year mosquito season in McLean County, ND starts around May 6 and ends around October 3, about 21 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in McLean County, and when
- Start tipping out standing water weekly by April 22.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 3.
- 15 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July, and check ND spray notices.
McLean County against the rest of ND
McLean County has the 21st longest season of 53 ND counties, at 150 days against 160 in Sheridan County and 135 in Rolette County. Its mean temperature is 41.4°F.
- Billings County: May 6 to October 3 (150 days, 1 WNV)
- Golden Valley County: May 6 to October 3 (150 days, 2 WNV)
- Barnes County: May 6 to October 2 (149 days, 15 WNV)
- Eddy County: May 6 to October 1 (149 days, 0 WNV)
West Nile in McLean County
From 1999 to 2025, CDC ArboNET counted 84 human West Nile cases in McLean County (28 neuroinvasive) across 17 years. The worst was 2003 with 28; the latest was 2025.
More: how the dates are worked out · reading the West Nile counts.