Chicago Heat Index Today
Updated planning preview · 7:00 PM forecast from WeatherAPI
Heat index
66°F
Low
Routine outdoor plans are generally reasonable.
Temperature
66°F
Humidity
49%
Estimated WBGT
14.3°C
UV index
0.0
Best outdoor window
5:00 PM–9:00 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 |
|---|---|---|---|---|---|
| 7 AM | 57°F | 57°F | 12.5°C | 0.0 | Low |
| 9 AM | 59°F | 59°F | 13.5°C | 0.9 | Low |
| 11 AM | 62°F | 62°F | 14.4°C | 3.2 | Low |
| 1 PM | 63°F | 63°F | 14.6°C | 4.5 | Low |
| 3 PM | 63°F | 63°F | 14.4°C | 2.8 | Low |
| 5 PM | 62°F | 62°F | 14.0°C | 0.6 | Low |
| 7 AM | 54°F | 54°F | 11.2°C | 0.0 | Low |
| 9 AM | 58°F | 58°F | 12.9°C | 0.8 | Low |
Today's outlook
In Chicago, the highest modeled heat burden in this preview occurs around 9:00 AM. The recommended window is selected from the lowest combined risk score, temperature, and UV—not from generic city copy.
Three-day forecast
Sunday
Heat index up to 76°F
70°F / 58°F
LowMonday
Heat index up to 63°F
63°F / 57°F
LowTuesday
Heat index up to 75°F
71°F / 54°F
LowToday in Chicago
What changes across the day
Based on the available hourly WeatherAPI forecast
Peak heat index
63°F at 1:00 PM
The preview low is 54°F around 7:00 AM.
Feels-like difference
Matches air temp
Current humidity is 49%, one input that changes evaporative cooling.
Peak UV
4.5 at 1:00 PM
UV and heat are separate hazards; the lowest-heat hour may still need sun protection.
Tomorrow's direction
12°F cooler tomorrow
Today's forecast range is 58°F–70°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.
Local planning context
Planning for heat in Chicago, IL
Chicago heat risk can change quickly with humidity, cloud cover and the timing of a weather system. Use the hourly values rather than a single daily high, and reassess when the activity lasts into a warmer part of the day.
Forecasts describe outdoor conditions, not an individual's medical risk. Workload, duration, shade, clothing, acclimatization and health can change the appropriate decision.
Nearby forecasts
Keep planning
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