San Antonio Mosquito Forecast
Live mosquito activity levels for the San Antonio metro area, updated daily with real weather data.
San Antonio sits at a fascinating ecological crossroads that directly shapes its mosquito profile. The city straddles the Balcones Escarpment, the geological fault line where the limestone Texas Hill Country drops into the flat Gulf Coastal Plain. This transition zone means San Antonio's west and north sides, with their rocky, well-drained Hill Country terrain, experience meaningfully different mosquito pressure than the flatter, clay-soil east and south sides of the metro area.
With annual rainfall around 33 inches and moderate humidity compared to Gulf Coast cities, San Antonio falls squarely in the moderate-risk category for mosquito activity across Texas. The city is neither as dry as West Texas nor as saturated as the Upper Coast, creating a mosquito season that responds dramatically to rainfall patterns. In wet years, San Antonio can rival Houston for peak activity; in drought years, activity drops well below typical levels.
Current San Antonio Mosquito Forecast
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View San Antonio's Live Forecast →Mosquito Season in San Antonio
Mosquito season in San Antonio generally spans from late March through November, with peak activity between May and October. The city's subtropical climate keeps winter temperatures mild enough that some mosquito activity can persist into December in warmer years, though significant freezes in January and February typically reset populations.
The peak months, June through September, coincide with the hottest weather and the late-summer rain pattern that characterizes South-Central Texas. San Antonio often experiences its heaviest rainfall in May-June and again in September-October, bookending the driest and hottest period of July-August. This creates an interesting double-peak pattern in mosquito activity: a first surge after spring rains, a slight dip during the hottest and driest weeks of mid-summer, and a second surge when fall moisture returns.
Compared to Austin (80 miles north), San Antonio tends to run slightly warmer and drier, which in an average year produces comparable or slightly lower mosquito scores. Compared to Houston (200 miles east), San Antonio's mosquito season is notably less severe, the absence of Gulf moisture and bayou-style drainage makes a significant difference. Our model captures these regional gradients by using localized weather station data for each city.
What Makes San Antonio Unique
The Edwards Aquifer Connection: San Antonio sits directly on the Edwards Aquifer recharge zone, one of the most significant groundwater systems in the United States. Springs fed by the aquifer, including San Pedro Springs, one of the oldest known human settlements in North America, create year-round surface water that supports permanent mosquito populations even during dry periods. The San Antonio River itself is spring-fed and maintains flow year-round, providing consistent larval habitat through the downtown corridor and the famous River Walk area.
The Balcones Escarpment Effect: The geological divide running through San Antonio creates distinct mosquito zones within the same city. Northwest neighborhoods like Stone Oak and The Dominion sit on porous limestone that absorbs rainfall quickly, reducing standing water. Southeast neighborhoods near Brooks City Base and the Mission Reach sit on clay soils that hold water for days, creating far more breeding opportunities. This geological reality means your mosquito experience in San Antonio depends heavily on which part of the city you live in.
San Antonio's extensive greenway and creek system, including Salado Creek, Leon Creek, and Medio Creek, adds another layer of breeding habitat. These creeks wind through residential neighborhoods and park systems, and their riparian zones provide the shaded, humid microhabitats that mosquitoes need during the intense summer heat. The city's ongoing linear park and trail development along these creeks is excellent for recreation but does place more residents in closer contact with mosquito habitat.
Tips for San Antonio Residents
- Know your geology. If you live on the east or south side of San Antonio (clay soils), you need to be more aggressive about eliminating standing water than residents on the Hill Country limestone side. After a rain event, clay-soil properties can hold puddles for 3-5 days, plenty of time for mosquito larvae to develop.
- Watch the spring-fed areas. If you live near San Pedro Springs Park, Brackenridge Park, or along the San Antonio River corridor, you have year-round mosquito habitat nearby. Use repellent for evening walks along the River Walk or Mission Reach, even in months when the rest of the city has low activity.
- Time your outdoor events carefully. San Antonio's Fiesta season (April) and fall festival season overlap with active mosquito periods. If you are hosting or attending outdoor events, plan for peak biting times at dawn and dusk, and consider citronella or fan-based solutions for patio gatherings.
- Maintain swimming pools and water features. San Antonio's popularity of backyard pools and fountains creates abundant mosquito breeding sites when water treatment lapses. An untreated pool can produce thousands of mosquitoes per week. If you are leaving town, ensure your pool pump is running or add mosquito dunks.
- Check your rain barrels and irrigation systems. Many San Antonio residents use rain barrels for drought-conscious landscaping. These are excellent mosquito breeding sites unless properly screened or treated with BTI dunks. Check all stored water weekly during the warm months.
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