Mosquito season in Le Sueur County, MN: when it starts and ends
Mosquito months in Le Sueur County
In a normal year mosquito season in Le Sueur County, MN starts around April 28 and ends around October 9, about 23 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Le Sueur County, and when
- Start tipping out standing water weekly by April 14.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 9.
- 4 West Nile cases since 2016 (last 2025): you should use repellent at dusk July to July, more so if over 60.
Le Sueur County against the rest of MN
Le Sueur County has the 30th longest season of 87 MN counties, at 164 days against 176 in Winona County and 118 in Cook County. Its mean temperature is 44.1°F.
- Anoka County: April 28 to October 9 (164 days, 23 WNV)
- Big Stone County: April 28 to October 9 (164 days, 5 WNV)
- Olmsted County: April 28 to October 9 (164 days, 2 WNV)
- Pipestone County: April 28 to October 9 (164 days, 4 WNV)
West Nile in Le Sueur County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Le Sueur County (1 neuroinvasive) across 5 years. The worst was 2025 with 1; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.