Mosquito season in Harrison County, TX: when it starts and ends
Mosquito months in Harrison County
In a normal year mosquito season in Harrison County, TX starts around March 5 and ends around November 24, about 38 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Harrison County, and when
- Start tipping out standing water weekly by February 19.
- Book any yard treatment for early March, ahead of the July peak.
- Repellent can go away after November 24.
- 3 West Nile cases since 2016 (last 2025): you should use repellent at dusk May to September, more so if over 60.
Harrison County against the rest of TX
Harrison County has the 136th longest season of 254 TX counties, at 264 days against 365 in Cameron County and 191 in Lipscomb County. Its mean temperature is 64.4°F.
- Marion County: March 3 to November 22 (264 days, 0 WNV)
- Cooke County: March 5 to November 24 (264 days, 8 WNV)
- Henderson County: March 5 to November 24 (264 days, 9 WNV)
- Johnson County: March 6 to November 25 (264 days, 17 WNV)
West Nile in Harrison County
From 1999 to 2025, CDC ArboNET counted 12 human West Nile cases in Harrison County (8 neuroinvasive) across 4 years. The worst was 2012 with 6; the latest was 2025.
Background: when mosquitoes go away for the winter; how the dates are worked out.