Mosquito season in Sheridan County, NE: when it starts and ends
Mosquito months in Sheridan County
In a normal year mosquito season in Sheridan County, NE starts around May 5 and ends around October 4, about 22 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Sheridan County, and when
- Start tipping out standing water weekly by April 21.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 4.
- 5 West Nile cases since 2016 (last 2025): you should use repellent at dusk July to August, more so if over 60.
Sheridan County against the rest of NE
Sheridan County has the 91st longest season of 93 NE counties, at 152 days against 200 in Richardson County and 127 in Sioux County. Its mean temperature is 46.8°F.
- Dawes County: May 5 to October 7 (155 days, 5 WNV)
- Kimball County: May 6 to October 6 (153 days, 2 WNV)
- Banner County: May 12 to September 29 (140 days, 1 WNV)
- Sioux County: May 17 to September 21 (127 days, 2 WNV)
West Nile in Sheridan County
From 1999 to 2025, CDC ArboNET counted 31 human West Nile cases in Sheridan County (8 neuroinvasive) across 10 years. The worst was 2003 with 9; the latest was 2025.
More: how the dates are worked out · reading the West Nile counts.