Mosquito season in Franklin County, IA: when it starts and ends
Mosquito months in Franklin County
In a normal year mosquito season in Franklin County, IA starts around April 23 and ends around October 15, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Franklin 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 15.
- 1 West Nile case since 2016 (last 2018): you should use repellent at dusk July to August, more so if over 60.
Franklin County against the rest of IA
Franklin County has the 75th longest season of 99 IA counties, at 174 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 46.6°F.
- Floyd County: April 22 to October 14 (174 days, 1 WNV)
- Bremer County: April 23 to October 14 (174 days, 4 WNV)
- Sac County: April 23 to October 14 (174 days, 0 WNV)
- Cass County: April 22 to October 12 (173 days, 0 WNV)
West Nile in Franklin County
From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in Franklin County (2 neuroinvasive) across 3 years. The worst was 2018 with 1; the latest was 2018.
See how the dates are worked out, and when the season starts across the US.