When is mosquito season in southwest Dallas?
Mosquitoes in Dallas County usually build from April, peak in the heat from June through September, and taper off after the first fall cold fronts. Dallas County Health and Human Services traps and tests mosquitoes roughly from April to mid-November, which tracks the season well. A warm fall or a wet October can stretch it.
Rain timing matters more than the calendar. In summer heat, puddles and containers can turn out a new batch of adults in about a week. Booking a visit right after a wet spell, rather than just before one, catches more of that wave.
Mild winters do not end the problem entirely. On warm January and February afternoons, a few mosquitoes can still bite in sheltered yards, but numbers do not climb until spring warmth settles in for good.
Is West Nile virus a concern in Dallas County?
Yes. Dallas County was at the center of the 2012 West Nile outbreak, with more than 270 confirmed cases by late August, about a quarter of all U.S. cases at that point. Aerial spraying began on August 16, 2012, Dallas' first since 1966. Positive mosquito traps and human cases are still reported in many summers.
In 2026, Dallas County Health and Human Services confirmed the county's first human case on August 11, when 167 positive mosquito pools had already been found. In 2025 the first human case was announced on July 31 and the first death in October. Counts change through the season, so check DCHHS and the Texas Department of State Health Services for current numbers.
The West Nile mosquito guide explains how county trapping works and what a positive trap near your street means.
Do city spray trucks replace a yard treatment?
No. After positive traps, the City of Dallas and nearby cities post notices and may spray from trucks along streets at night. That spray targets adult mosquitoes flying in the open air for a short time. It does not reach the shrubs, gutters and containers in your backyard, where most of the mosquitoes biting you rest and breed.
Check your own city's notices for spray nights and areas; Dallas, Duncanville, DeSoto and Cedar Hill each post their own. A private yard treatment is scheduled with you and planned around your pets, gardens and pool.
How little water can breed mosquitoes?
Very little. Asian tiger mosquitoes lay eggs in a bottle cap of water, a clogged gutter, a plant saucer or the fold of a pool cover. Southern house mosquitoes prefer bigger, dirtier water, such as storm drains, ditches and neglected pools. Dumping and scrubbing containers once a week is the cheapest mosquito control there is.
Scrubbing matters because tiger mosquito eggs stick to container walls above the waterline and hatch when the next rain refills them.
- Tip and scrub bird baths, pet dishes and plant saucers weekly
- Clear gutters and downspout extensions, especially under live oaks and pecans
- Drill drain holes in tire swings, recycling bins and buckets
- Keep pools running or tightly covered, and empty kiddie pools after use
- Fill low spots in the lawn where water sits after storms
Can yards near Mountain Creek, Joe Pool Lake or the Trinity be treated?
Yes, but the yard is only part of the picture. Homes near Joe Pool Lake, Mountain Creek or the Trinity levees get mosquitoes flying in from water nobody can treat. Treating resting areas in your yard on a regular schedule keeps bites down, though you should expect more pressure than a lot far from water.
Labels limit how close certain products can go to lakes, creeks and ponds, and the technician keeps treatments back from water as required. Public land, levees and parks are never part of a private yard service. Homes in Mountain Creek and along the Cedar Hill side of the lake usually do better on a full-season program than with single visits.
