San Jose Heat Index Today
Updated planning preview · 4:00 PM forecast from WeatherAPI
Heat index
78°F
Low
Routine outdoor plans are generally reasonable.
Temperature
76°F
Humidity
55%
Estimated WBGT
22.0°C
UV index
4.3
Best outdoor window
6:00 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 |
|---|---|---|---|---|---|
| 4 PM | 76°F | 78°F | 22.0°C | 4.3 | Low |
| 6 PM | 71°F | 76°F | 20.0°C | 0.9 | Low |
| 7 AM | 57°F | 57°F | 14.6°C | 0.1 | Low |
| 9 AM | 65°F | 65°F | 17.0°C | 1.7 | Low |
| 11 AM | 75°F | 77°F | 20.0°C | 5.6 | Low |
| 1 PM | 83°F | 81°F | 22.4°C | 8.5 | Moderate |
| 3 PM | 84°F | 82°F | 22.8°C | 6.5 | Moderate |
| 5 PM | 79°F | 79°F | 21.7°C | 2.4 | Low |
Today's outlook
In San Jose, the highest modeled heat burden in this preview occurs around 3:00 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 78°F
76° / 57°
LowFriday
Heat index up to 83°F
85° / 57°
ModerateSaturday
Heat index up to 88°F
92° / 55°
ModerateToday in San Jose
What changes across the day
Based on the available hourly WeatherAPI forecast
Peak heat index
82°F at 3:00 PM
The preview low is 57°F around 7:00 AM.
Feels-like difference
2°F above air temp
Current humidity is 55%, one input that changes evaporative cooling.
Peak UV
8.5 at 1:00 PM
UV and heat are separate hazards; the lowest-heat hour may still need sun protection.
Tomorrow's direction
4°F hotter tomorrow
Today's forecast range is 57–76°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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