Mosquito season in Calumet County, WI: when it starts and ends

Mosquito months in Calumet County

In a normal year mosquito season in Calumet County, WI starts around April 30 and ends around October 12, about 24 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 Calumet County, and when

• Start tipping out standing water weekly by April 16.
• Book any yard treatment for late April, ahead of the July peak.
• Repellent can go away after October 12.
• 3 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to July, more so if over 60.

Calumet County against the rest of WI

Calumet County has the 25th longest season of 72 WI counties, at 165 days against 180 in La Crosse County and 139 in Rusk County. Its mean temperature is 45.6°F.

• Dodge County: April 29 to October 11 (165 days, 1 WNV)
• Green Lake County: April 29 to October 11 (165 days, 0 WNV)
• Washington County: May 1 to October 12 (165 days, 2 WNV)
• Adams County: April 29 to October 10 (164 days, 1 WNV)

West Nile in Calumet County

From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Calumet County (3 neuroinvasive) across 3 years. The worst was 2024 with 2; the latest was 2024.

More: how the dates are worked out · when the season starts across the US.