Mosquito season in Mille Lacs County, MN: when it starts and ends

Mosquito months in Mille Lacs County

In a normal year mosquito season in Mille Lacs County, MN starts around May 4 and ends around October 4, about 22 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Mille Lacs County, and when

• Start tipping out standing water weekly by April 20.
• Book any yard treatment for early May, ahead of the July peak.
• Repellent can go away after October 4.
• 3 West Nile cases since 2016 (last 2024): you should use repellent at dusk July, more so if over 60.

Mille Lacs County against the rest of MN

Mille Lacs County has the 62nd longest season of 87 MN counties, at 153 days against 176 in Winona County and 118 in Cook County. Its mean temperature is 41.7°F.

• Cass County: May 3 to October 4 (153 days, 4 WNV)
• Kanabec County: May 4 to October 4 (153 days, 0 WNV)
• Becker County: May 5 to October 3 (151 days, 5 WNV)
• Otter Tail County: May 5 to October 3 (151 days, 9 WNV)

West Nile in Mille Lacs County

From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Mille Lacs County (5 neuroinvasive) across 6 years. The worst was 2024 with 1; the latest was 2024.

See how the dates are worked out, and when mosquitoes go away for the winter.