Saint Louis Heat Index Today
Updated planning preview · 6:00 PM forecast from WeatherAPI
Heat index
92°F
High
Reduce prolonged exertion and plan extra recovery.
Temperature
88°F
Humidity
49%
Estimated WBGT
27.4°C
UV index
0.7
Best outdoor window
7:00 AM–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 | 88°F | 92°F | 27.4°C | 0.7 | High |
| 7 AM | 66°F | 66°F | 19.7°C | 0.1 | Low |
| 9 AM | 72°F | 76°F | 21.0°C | 1.9 | Low |
| 11 AM | 79°F | 80°F | 23.1°C | 5.7 | Moderate |
| 1 PM | 84°F | 84°F | 24.5°C | 7.9 | Moderate |
| 3 PM | 86°F | 86°F | 25.3°C | 5.8 | Moderate |
| 5 PM | 86°F | 86°F | 25.3°C | 1.9 | Moderate |
| 7 PM | 82°F | 84°F | 24.8°C | 0.1 | Moderate |
Today's outlook
In Saint Louis, 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 100°F
90° / 69°
HighFriday
Heat index up to 87°F
86° / 66°
ModerateSaturday
Heat index up to 88°F
87° / 71°
ModerateToday in Saint Louis
What changes across the day
Based on the available hourly WeatherAPI forecast
Peak heat index
92°F at 6:00 PM
The preview low is 66°F around 7:00 AM.
Feels-like difference
4°F above air temp
Current humidity is 49%, one input that changes evaporative cooling.
Peak UV
7.9 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 69–90°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.
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