Mosquito season in Nemaha County, NE: when it starts and ends

Mosquito months in Nemaha County

In a normal year mosquito season in Nemaha County, NE starts around April 15 and ends around October 20, about 27 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Nemaha County, and when

• Start tipping out standing water weekly by April 1.
• Book any yard treatment for mid April, ahead of the July peak.
• Repellent can go away after October 20.
• 3 West Nile cases since 2016 (last 2018): you should use repellent at dusk June to August, more so if over 60.

Nemaha County against the rest of NE

Nemaha County has the 22nd longest season of 93 NE counties, at 188 days against 200 in Richardson County and 127 in Sioux County. Its mean temperature is 52.2°F.

• Washington County: April 15 to October 21 (189 days, 17 WNV)
• Otoe County: April 16 to October 22 (189 days, 3 WNV)
• Hitchcock County: April 16 to October 21 (188 days, 3 WNV)
• Polk County: April 16 to October 21 (188 days, 5 WNV)

West Nile in Nemaha County

From 1999 to 2025, CDC ArboNET counted 10 human West Nile cases in Nemaha County (1 neuroinvasive) across 5 years. The worst was 2018 with 3; the latest was 2018.

See how the dates are worked out, and when the season starts across the US.