San Antonio Heat Index Today
Updated planning preview · 6:00 PM forecast from WeatherAPI
Heat index
103°F
Very high
Reschedule strenuous activity when possible.
Temperature
101°F
Humidity
27%
Estimated WBGT
29.9°C
UV index
1.5
Best outdoor window
8:00 PM–11:00 AM
Lowest combined heat and UV load in the available hourly preview.
Hourly heat risk
WBGT values are labeled as modeled estimates until a provider supplies measured readings.
| Time | Temperature | Heat index | Estimated WBGT | UV | Risk |
|---|---|---|---|---|---|
| 6 PM | 101°F | 103°F | 29.9°C | 1.5 | Very high |
| 8 PM | 95°F | 96°F | 28.1°C | 0.0 | High |
| 9 AM | 82°F | 85°F | 25.5°C | 1.3 | Moderate |
| 11 AM | 90°F | 92°F | 27.4°C | 6.0 | High |
| 1 PM | 97°F | 99°F | 28.9°C | 10.2 | High |
| 3 PM | 101°F | 102°F | 29.5°C | 8.7 | High |
| 5 PM | 102°F | 102°F | 29.2°C | 3.2 | High |
| 7 PM | 99°F | 98°F | 28.1°C | 0.3 | High |
Today's outlook
In San Antonio, the highest modeled heat burden in this preview occurs around 6:00 PM. The recommended window is selected from the lowest combined risk score, temperature, and UV—not from generic city copy.
Three-day forecast
Thursday
Heat index up to 115°F
107° / 77°
Very highFriday
Heat index up to 102°F
102° / 78°
HighSaturday
Heat index up to 101°F
102° / 78°
HighToday in San Antonio
What changes across the day
Based on the available hourly WeatherAPI forecast
Peak heat index
103°F at 6:00 PM
The preview low is 85°F around 9:00 AM.
Feels-like difference
2°F above air temp
Current humidity is 27%, one input that changes evaporative cooling.
Peak UV
10.2 at 1:00 PM
UV and heat are separate hazards; the lowest-heat hour may still need sun protection.
Tomorrow's direction
13°F cooler tomorrow
Today's forecast range is 77–107°F.
Where these numbers come from
WeatherAPI supplies the forecast. HeatGuard calculates heat-index risk and models WBGT from forecast temperature, humidity and a daytime solar allowance. Modeled WBGT is not an on-site globe-thermometer reading.
Keep planning
Track San Antonio in HeatGuard
Save this location and get alerts as conditions change.