Mosquito season in Ramsey County, ND: when it starts and ends
Mosquito months in Ramsey County
In a normal year mosquito season in Ramsey County, ND starts around May 7 and ends around September 30, about 21 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Ramsey County, and when
- Start tipping out standing water weekly by April 23.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after September 30.
- 12 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July, and check ND spray notices.
Ramsey County against the rest of ND
Ramsey County has the 34th longest season of 53 ND counties, at 146 days against 160 in Sheridan County and 135 in Rolette County. Its mean temperature is 39.3°F.
- Griggs County: May 7 to October 1 (147 days, 6 WNV)
- Stark County: May 8 to October 2 (147 days, 21 WNV)
- Steele County: May 7 to September 30 (146 days, 2 WNV)
- Nelson County: May 7 to September 30 (145 days, 1 WNV)
West Nile in Ramsey County
From 1999 to 2025, CDC ArboNET counted 44 human West Nile cases in Ramsey County (6 neuroinvasive) across 11 years. The worst was 2003 with 12; the latest was 2024.
More: how the dates are worked out · reading the West Nile counts.