Mosquito season in Pembina County, ND: when it starts and ends
Mosquito months in Pembina County
In a normal year mosquito season in Pembina County, ND starts around May 8 and ends around September 29, about 21 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Pembina County, and when
- Start tipping out standing water weekly by April 24.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after September 29.
- 2 West Nile cases since 2016 (last 2025): you should use repellent at dusk July, more so if over 60.
Pembina County against the rest of ND
Pembina County has the 40th longest season of 53 ND counties, at 145 days against 160 in Sheridan County and 135 in Rolette County. Its mean temperature is 38.6°F.
- Benson County: May 8 to September 30 (145 days, 4 WNV)
- Morton County: May 8 to September 30 (145 days, 42 WNV)
- Bowman County: May 9 to October 2 (145 days, 3 WNV)
- Dunn County: May 9 to September 30 (144 days, 3 WNV)
West Nile in Pembina County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Pembina County (1 neuroinvasive) across 3 years. The worst was 2007 with 3; the latest was 2025.
Background: when mosquitoes go away for the winter; how the dates are worked out.