Mosquito season in Washington County, MS: when it starts and ends

Mosquito months in Washington County

In a normal year mosquito season in Washington County, MS starts around March 2 and ends around November 26, about 38 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 Washington County, and when

• Start tipping out standing water weekly by February 16.
• Book any yard treatment for early March, ahead of the July peak.
• Repellent can go away after November 26.
• 4 West Nile cases since 2016 (last 2025): you should use repellent at dusk May to September, more so if over 60.

Washington County against the rest of MS

Washington County has the 34th longest season of 82 MS counties, at 269 days against 333 in Harrison County and 221 in Tishomingo County. Its mean temperature is 64.1°F.

• Greene County: March 2 to November 26 (269 days, 0 WNV)
• Perry County: March 2 to November 26 (269 days, 2 WNV)
• Lawrence County: February 27 to November 22 (268 days, 2 WNV)
• Jones County: February 28 to November 23 (268 days, 3 WNV)

West Nile in Washington County

From 1999 to 2025, CDC ArboNET counted 35 human West Nile cases in Washington County (18 neuroinvasive) across 13 years. The worst was 2004 with 6; the latest was 2025.

See how the dates are worked out, and reading the West Nile counts.