Mosquito season in Union County, AR: when it starts and ends
Mosquito months in Union County
In a normal year mosquito season in Union County, AR starts around March 4 and ends around November 21, about 37 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Union County, and when
- Start tipping out standing water weekly by February 18.
- Book any yard treatment for early March, ahead of the July peak.
- Repellent can go away after November 21.
- 7 West Nile cases since 2016 (last 2025): you should use repellent at dusk May to September, more so if over 60.
Union County against the rest of AR
Union County has the 12th longest season of 75 AR counties, at 262 days against 274 in Chicot County and 211 in Washington County. Its mean temperature is 63.8°F.
- Lafayette County: March 5 to November 25 (265 days, 1 WNV)
- Crittenden County: March 4 to November 22 (263 days, 1 WNV)
- Phillips County: March 5 to November 22 (262 days, 0 WNV)
- Bradley County: March 6 to November 23 (262 days, 1 WNV)
West Nile in Union County
From 1999 to 2025, CDC ArboNET counted 32 human West Nile cases in Union County (18 neuroinvasive) across 15 years. The worst was 2002 with 7; the latest was 2025.
See how the dates are worked out, and reading the West Nile counts.