Mosquito season in Itasca County, MN: when it starts and ends
Mosquito months in Itasca County
In a normal year mosquito season in Itasca County, MN starts around May 10 and ends around September 29, about 20 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Itasca County, and when
- Start tipping out standing water weekly by April 26.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after September 29.
- 5 West Nile cases since 2016 (last 2025): you should use repellent at dusk July, more so if over 60.
Itasca County against the rest of MN
Itasca County has the 81st longest season of 87 MN counties, at 142 days against 176 in Winona County and 118 in Cook County. Its mean temperature is 38.9°F.
- Clearwater County: May 9 to September 29 (143 days, 0 WNV)
- Lake of the Woods County: May 9 to September 29 (143 days, 0 WNV)
- Roseau County: May 10 to September 28 (141 days, 2 WNV)
- Carlton County: May 12 to September 30 (141 days, 0 WNV)
West Nile in Itasca County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Itasca County (4 neuroinvasive) across 3 years. The worst was 2023 with 3; the latest was 2025.
More: how the dates are worked out · reading the West Nile counts.