Mosquito season in Boone County, IA: when it starts and ends
Mosquito months in Boone County
In a normal year mosquito season in Boone County, IA starts around April 18 and ends around October 18, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Boone County, and when
- Start tipping out standing water weekly by April 4.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 18.
- 3 West Nile cases since 2016 (last 2025): you should use repellent at dusk July to August, more so if over 60.
Boone County against the rest of IA
Boone County has the 40th longest season of 99 IA counties, at 182 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 48.3°F.
- Jasper County: April 18 to October 18 (183 days, 1 WNV)
- Decatur County: April 19 to October 19 (183 days, 0 WNV)
- O'Brien County: April 18 to October 18 (182 days, 5 WNV)
- Harrison County: April 19 to October 18 (182 days, 7 WNV)
West Nile in Boone County
From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in Boone County (5 neuroinvasive) across 6 years. The worst was 2003 with 2; the latest was 2025.
See how the dates are worked out, and when the season starts across the US.