Today's Mosquito Risk in Texas: Real-Time Forecast & Activity Map
Check your ZIP code for local mosquito activity, West Nile risk, and prevention insights.
Built from CDC and NOAA data
Mosquito Surveillance Insights
- Annual WNV Cases
- about 150 to 300 confirmed cases annually
- highest absolute count in the Southwest
- Based on CDC ArboNET surveillance data
- Risk Tier
- Tier 1: Peak Pressure
- Local dengue transmission documented in the Rio Grande Valley; Houston and Dallas drive most absolute case counts.
- Per mosquito-risk-model regional tier
- Highest-Risk Areas
- Harris, Dallas, Bexar, Travis, Tarrant (WNV); Hidalgo and Cameron (dengue); Galveston and Brazoria (Gulf Coast and post-hurricane)
Current Situation in Texas
Texas is the heaviest absolute WNV burden in the Southwest, with roughly 150 to 300 confirmed human cases annually and the largest population at risk in the region. The state runs as several mosquito climates stitched together: the humid Gulf Coast at Houston and Galveston, the Hill Country springs around Austin and San Antonio, the East Texas Pineywoods, the High Plains, the Trans-Pecos desert, and the Rio Grande Valley at the southern tip. Aedes aegypti is established statewide and sustains documented local dengue transmission in Hidalgo and Cameron counties along the lower Rio Grande. Aedes albopictus is statewide. Cx. quinquefasciatus drives WNV transmission in Houston, Dallas, San Antonio, and Austin. Cx. tarsalis fills in across irrigated farmland in West Texas. Hurricane Harvey in 2017 produced one of the largest Psorophora floodwater blooms on record. Biting season runs April through November, with year-round activity on the Gulf Coast and in the Rio Grande Valley.
Snapshot of the current mosquito situation in Texas, drawn from CDC ArboNET surveillance and the regional risk model.
- Risk Level
- Very High
- Peak Activity
- April through October
- Dominant Vector
- Southern House Mosquito (Culex quinquefasciatus); Yellow Fever Mosquito (Aedes aegypti) statewide
Where Mosquitoes Breed in Texas
Texas mosquito habitat is the most varied in the country outside Florida. The Gulf Coast salt marsh from Galveston Bay through Matagorda and the Padre Island lagoons produces dense Aedes sollicitans and Aedes taeniorhynchus. The Big Thicket pine and cypress swamps of East Texas hold Culiseta and woodland Aedes off bottomland forest. The Hill Country springs and Edwards Plateau cave systems sustain seasonal Cx. quinquefasciatus through limestone-fed creeks. The Rio Grande Valley citrus and sugarcane belt below Brownsville carries year-round Aedes aegypti and is the dengue focus. The Trans-Pecos and Llano Estacado high plains stay dry except where irrigation pulls Cx. tarsalis off cotton and alfalfa fields. The Trinity, Brazos, and San Antonio River bottomlands produce Aedes vexans floodwater hatches. Storm drains and abandoned pools across Houston, Dallas, San Antonio, Austin, and Fort Worth carry the urban Aedes albopictus and Cx. quinquefasciatus load.
Hotspot Counties & Areas
- Harris County (Houston metro, Galveston Bay edge)
- Dallas County (Dallas metro, Trinity River)
- Bexar County (San Antonio, San Antonio River)
- Travis County (Austin, Hill Country edge)
- Tarrant County (Fort Worth, Trinity River)
- Hidalgo and Cameron counties (Rio Grande Valley, dengue focus)
- Galveston County (Gulf Coast salt marsh)
- Big Thicket National Preserve (East Texas Pineywoods)
Seasonal Activity Pattern
Biting starts in early April across the Gulf Coast and the Rio Grande Valley, peaks late July through September in the urban metros, and tapers through November. The Coast and the lower Rio Grande Valley see year-round Aedes aegypti biting in mild winters. WNV cases concentrate from July through October across Houston (Harris), Dallas (Dallas), Tarrant, Bexar, and Travis counties. Local dengue transmission in Hidalgo and Cameron counties tends to flare in late summer. Hurricane and tropical-storm flooding from June through October triggers explosive Psorophora and Aedes vexans hatches that overwhelm county spray operations within days of landfall. The Trans-Pecos and Llano Estacado run dry and quiet outside the brief monsoon-edge rains of late summer.
Monthly Biting Intensity (Southwest)
Texas Mosquito Risk Profile
- WNV burden level
- Very High
- about 150 to 300 confirmed cases annually; highest absolute count in the Southwest
- EEE risk
- Rare
- Peak biting season
- April through November; near year-round on Gulf Coast
- Top urban risk areas
- Houston (Harris)
- San Antonio (Bexar)
- Dallas (Dallas)
- Austin (Travis)
Signature habitat: Gulf Coast salt marsh, Hill Country springs, Rio Grande Valley irrigated farms, urban Houston and Dallas storm drains.
Climate driver: Local dengue transmission documented in the Rio Grande Valley; Houston and Dallas drive most absolute case counts.
Check Your Local Mosquito Risk
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Common Mosquitoes in Texas
Understanding which mosquitoes are active in Texas helps you identify threats and take appropriate precautions. Click any card for details.
Southern House Mosquito
Culex quinquefasciatus
Risk: West Nile virus, St. Louis encephalitis, dog heartworm.
Key feature: Medium brown body with banded abdominal segments and no leg stripes.
Active: Year-round in the deep South; summer peak elsewhere. Most active from dusk through the first few hours after sunset.
Yellow Fever Mosquito
Aedes aegypti
Risk: Zika, dengue, yellow fever, chikungunya.
Key feature: Black body with white lyre-shaped markings on the thorax.
Active: Year-round in southern Florida and the Gulf; summer-only further north.
West Nile Virus
Vector: Southern House Mosquito
West Nile Virus
The most common mosquito-borne illness in the US. About 80% of infections cause no symptoms; less than 1% develop neuroinvasive disease.
What to watch for
- Onset typically 2 to 15 days after a bite
- Most cases mild or asymptomatic, small fraction severe
- Neurological signs (severe headache, neck stiffness, confusion) need ER care
Breaking the Cycle in Texas
The mosquito lifecycle takes about a week. These habits cut local biting pressure faster than anything else, building multiple layers of protection.
Drain the Yard Weekly
Empty buckets, planter saucers, kiddie pools, tarps, and clogged gutters. A week of standing water is one full mosquito generation.
Repel Before Going Out
EPA-registered DEET (20-30%), picaridin (20%), IR3535, or oil of lemon eucalyptus. Apply before going outside, especially at dusk and dawn.
Seal the House
Window and door screens with no tears. AC and porch fans both work. Mosquitoes struggle to fly upwind even at 1-2 mph air speed.
Treat Outdoor Clothing
Permethrin-treated long sleeves and pants for evening yard work, hiking, or fishing. Remains effective through 70+ wash cycles.
If You Develop Symptoms
Most mosquito bites are harmless. A small fraction can transmit illness, and knowing the timeline matters more than panicking at every itch.Five things to know.
Watch for fever
Fever, body aches, headache, or fatigue 2 to 15 days after a bite. West Nile often feels like flu, and most infections never get diagnosed.
Note where and when
A rough record of where and when you got bitten helps your doctor decide what to test for. Date, location, mosquito-heavy areas you visited.
Get help fast for neuro signs
Severe headache, neck stiffness, confusion, vision changes, or sudden muscle weakness can mean neuroinvasive WNV or EEE. Both are medical emergencies.
Pregnant exposure?
If pregnant and bitten in an area with documented Zika or local dengue transmission, mention to your OB. Same goes for travel exposure.
Children and seniors
Higher risk of severe disease from WNV, EEE, and dengue in adults over 60 and children under 5. Early call to the pediatrician or PCP if symptoms appear.
Heading to a lake in Texas?
Live water temperatures and swim conditions for Lake Travis, Lake Conroe.
See Texas lake temperaturesWhen does mosquito season end in Texas?
Mosquito activity winds down after the first hard freeze, which in Texas typically arrives around Nov 20. See the local first-frost window and city-by-city freeze dates.
Texas first frost datesAlso worried about ticks in Texas?
Lyme disease risk and tick activity track different seasonal patterns than mosquitoes. See your Texas tick forecast.
View Texas tick forecastStay Safe in Texas
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