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

Mosquito months in Harrison County

In a normal year mosquito season in Harrison County, MS starts around February 1 and ends around December 31, about 48 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 Harrison County, and when

• Start tipping out standing water weekly by January 18.
• Book any yard treatment for early February, ahead of the July peak.
• Repellent can go away after December 31.
• 7 West Nile cases since 2016 (last 2025): you should use repellent at dusk May to October, more so if over 60.

Harrison County against the rest of MS

Harrison County has the 1st longest season of 82 MS counties, at 333 days against 333 in Harrison County and 221 in Tishomingo County. Its mean temperature is 68.3°F.

• Simpson County: February 23 to January 4 (315 days, 1 WNV)
• Stone County: February 27 to January 8 (315 days, 1 WNV)

West Nile in Harrison County

From 1999 to 2025, CDC ArboNET counted 59 human West Nile cases in Harrison County (36 neuroinvasive) across 12 years. The worst was 2003 with 17; the latest was 2025.

See how the dates are worked out, and where mosquitoes never stop.