Mosquito season in Sherman County, NE: when it starts and ends
Mosquito months in Sherman County
In a normal year mosquito season in Sherman County, NE starts around April 21 and ends around October 17, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Sherman 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 17.
- 2 West Nile cases since 2016 (last 2022): you should use repellent at dusk June to August, more so if over 60.
Sherman County against the rest of NE
Sherman County has the 48th longest season of 93 NE counties, at 179 days against 200 in Richardson County and 127 in Sioux County. Its mean temperature is 50°F.
- Knox County: April 20 to October 16 (179 days, 10 WNV)
- Madison County: April 20 to October 16 (179 days, 18 WNV)
- Nance County: April 20 to October 15 (178 days, 4 WNV)
- Pierce County: April 21 to October 16 (178 days, 4 WNV)
West Nile in Sherman County
From 1999 to 2025, CDC ArboNET counted 20 human West Nile cases in Sherman County (1 neuroinvasive) across 7 years. The worst was 2003 with 14; the latest was 2022.
More: how the dates are worked out · when the season starts across the US.