Mosquito season in Divide County, ND: when it starts and ends
Mosquito months in Divide County
In a normal year mosquito season in Divide County, ND starts around May 9 and ends around September 27, about 20 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Divide County, and when
- Start tipping out standing water weekly by April 25.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after September 27.
- 2 West Nile cases since 2016 (last 2025): you should use repellent at dusk July, more so if over 60.
Divide County against the rest of ND
Divide County has the 45th longest season of 53 ND counties, at 141 days against 160 in Sheridan County and 135 in Rolette County. Its mean temperature is 39.1°F.
- Grant County: May 11 to October 2 (144 days, 1 WNV)
- Renville County: May 9 to September 28 (142 days, 0 WNV)
- Mercer County: May 11 to September 28 (140 days, 25 WNV)
- Williams County: May 11 to September 28 (140 days, 31 WNV)
West Nile in Divide County
From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in Divide County (1 neuroinvasive) across 5 years. The worst was 2025 with 2; the latest was 2025.
More: how the dates are worked out · when the season starts across the US.