Mosquito season in Dallas County, TX: when it starts and ends

Mosquito months in Dallas County

In a normal year mosquito season in Dallas County, TX starts around February 18 and ends around December 12, about 42 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 Dallas County, and when

• Start tipping out standing water weekly by February 4.
• Book any yard treatment for mid February, ahead of the August peak.
• Repellent can go away after December 12.
• 219 West Nile cases since 2016: you should wear EPA-registered repellent at dusk May to September, and check TX spray notices.

Dallas County against the rest of TX

Dallas County has the 66th longest season of 254 TX counties, at 297 days against 365 in Cameron County and 191 in Lipscomb County. Its mean temperature is 67.4°F.

• Fayette County: February 15 to December 10 (298 days, 0 WNV)
• DeWitt County: February 15 to December 9 (297 days, 0 WNV)
• Kinney County: February 16 to December 6 (293 days, 0 WNV)
• Caldwell County: February 17 to December 6 (292 days, 1 WNV)

West Nile in Dallas County

From 1999 to 2025, CDC ArboNET counted 929 human West Nile cases in Dallas County (557 neuroinvasive) across 23 years. The worst was 2012 with 396; the latest was 2025.

Background: reading the West Nile counts; how the dates are worked out.