Mosquito season in Rock County, MN: when it starts and ends
Mosquito months in Rock County
In a normal year mosquito season in Rock County, MN starts around April 25 and ends around October 12, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Rock County, and when
- Start tipping out standing water weekly by April 11.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 12.
- 7 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.
Rock County against the rest of MN
Rock County has the 7th longest season of 87 MN counties, at 170 days against 176 in Winona County and 118 in Cook County. Its mean temperature is 46°F.
- Cottonwood County: April 25 to October 13 (171 days, 7 WNV)
- Martin County: April 25 to October 13 (171 days, 6 WNV)
- Hennepin County: April 25 to October 11 (169 days, 67 WNV)
- Watonwan County: April 26 to October 12 (169 days, 2 WNV)
West Nile in Rock County
From 1999 to 2025, CDC ArboNET counted 10 human West Nile cases in Rock County (7 neuroinvasive) across 7 years. The worst was 2016 with 3; the latest was 2024.
More: how the dates are worked out · reading the West Nile counts.