Mosquito season in Palo Alto County, IA: when it starts and ends
Mosquito months in Palo Alto County
In a normal year mosquito season in Palo Alto County, IA starts around April 21 and ends around October 16, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Palo Alto County, and when
- Start tipping out standing water weekly by April 7.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 16.
- 1 West Nile case since 2016 (last 2018): you should use repellent at dusk June to August, more so if over 60.
Palo Alto County against the rest of IA
Palo Alto County has the 53rd longest season of 99 IA counties, at 178 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 47.3°F.
- Woodbury County: April 20 to October 15 (178 days, 18 WNV)
- Jones County: April 21 to October 15 (178 days, 1 WNV)
- Tama County: April 21 to October 16 (178 days, 3 WNV)
- Dubuque County: April 21 to October 15 (177 days, 2 WNV)
West Nile in Palo Alto County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Palo Alto County (2 neuroinvasive) across 2 years. The worst was 2018 with 1; the latest was 2018.
More: how the dates are worked out · when the season starts across the US.