San Antonio Summer Heat: 98–99°F Average Highs, 110°F Extremes
San Antonio summers are consistently hot — humid subtropical climate means high temperatures and moisture.
Temperature Profile
| Month | Avg High | Avg Low | Record High | Record Low |
|---|
| June | 93°F (34°C) | 73°F (23°C) | 104°F | 50°F |
| July | 98°F (37°C) | 76°F (24°C) | 107°F | 60°F |
| August | 99°F (37°C) | 78°F (26°C) | 110°F | 62°F |
| September | 92°F (33°C) | 71°F (22°C) | 106°F | 45°F |
Heat Characteristics
- Heat index: Often 105–115°F (humidity 60–80%)
- 100°F+ days: 10–20/year (increasing trend)
- Nights: Rarely below 75°F in July/Aug — no relief
- Urban heat island: Downtown 2–5°F hotter than suburbs
Rain & Storms
- Annual rainfall: ~32 inches (810 mm)
- Summer pattern: Morning sun → afternoon thunderstorms (sea breeze + instability)
- Flash flooding: Low-lying areas; 1998, 2002, 2013, 2021 major events
- Texas Norther: Cold fronts dropping temps 20–30°F in hours; wind 40–50 mph
Winter Contrast
- January: Avg high 62°F, low 41°F
- Freezes: 10–15 nights/year; hard freeze (<28°F) every few years
- Record low: 0°F (1989, 2021)
Adaptation
- AC ubiquitous: 99% homes; central standard
- Outdoor life: Early morning/evening; shaded River Walk; water parks
- Infrastructure: Cool roofs, tree canopy programs, splash pads
- Health: Heat alerts (NWS); cooling centers; check on elderly
San Antonio's heat is manageable with preparation — but unforgiving to the unprepared.
Wanderlust World