Mosquito season in Bremer County, IA: when it starts and ends
Mosquito months in Bremer County
In a normal year mosquito season in Bremer County, IA starts around April 23 and ends around October 14, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Bremer County, and when
- Start tipping out standing water weekly by April 9.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 14.
- 4 West Nile cases since 2016 (last 2022): you should use repellent at dusk July to July, more so if over 60.
Bremer County against the rest of IA
Bremer County has the 74th longest season of 99 IA counties, at 174 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 46.4°F.
- Humboldt County: April 23 to October 15 (175 days, 3 WNV)
- Floyd County: April 22 to October 14 (174 days, 1 WNV)
- Franklin County: April 23 to October 15 (174 days, 1 WNV)
- Sac County: April 23 to October 14 (174 days, 0 WNV)
West Nile in Bremer County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Bremer County (2 neuroinvasive) across 3 years. The worst was 2018 with 3; the latest was 2022.
See how the dates are worked out, and reading the West Nile counts.