Mosquito season in Ogle County, IL: when it starts and ends
Mosquito months in Ogle County
In a normal year mosquito season in Ogle County, IL starts around April 19 and ends around October 19, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Ogle County, and when
- Start tipping out standing water weekly by April 5.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 19.
- 1 West Nile case since 2016 (last 2023): you should use repellent at dusk July to August, more so if over 60.
Ogle County against the rest of IL
Ogle County has the 92nd longest season of 102 IL counties, at 183 days against 232 in Pulaski County and 174 in Boone County. Its mean temperature is 48.9°F.
- Kendall County: April 18 to October 21 (186 days, 4 WNV)
- Kane County: April 19 to October 20 (184 days, 35 WNV)
- Lake County: April 22 to October 22 (183 days, 41 WNV)
- Lee County: April 20 to October 19 (182 days, 2 WNV)
West Nile in Ogle County
From 1999 to 2025, CDC ArboNET counted 4 human West Nile cases in Ogle County (4 neuroinvasive) across 4 years. The worst was 2023 with 1; the latest was 2023.
Background: when mosquitoes go away for the winter; how the dates are worked out.