Outdoor heat intelligence

Know your heat risk before you go outside.

Check heat index, WBGT, UV, and outdoor conditions before workouts, work, sports, hikes, and everyday plans.

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Phoenix, AZ

Featured forecast · 2 PM

Very high

Heat Index

117°F

Estimated WBGT

33°C

UV Index

Best outdoor window

6 AM–10 AM

Lower combined heat and UV load in this forecast.

2 PM

117°

4 PM

121°

6 PM

114°

6 AM

90°

8 AM

92°

10 AM

95°

12 PM

99°

2 PM

105°

LowModerateHighVery highExtreme

Forecast data by WeatherAPI.com

Phoenix is the featured example · Search to update the site

Understand the signal

Three measures. One clearer decision.

Heat index, WBGT, and UV answer different questions. HeatGuard keeps the distinctions visible instead of hiding them inside a single score.

Heat Index

How hot it feels when humidity limits evaporative cooling.

WBGT

A broader estimate of heat stress that can account for sun and wind.

UV Index

The expected intensity of ultraviolet radiation and sun exposure risk.

Plan the activity

Conditions change. Your plan should too.

Each activity page combines the same weather inputs with activity-specific exertion context and a lower-risk time window.

Running

Pace around heat and UV peaks.

Outdoor work

Plan demanding tasks and recovery.

Hiking

Check exposed trail hours before leaving.

Sports

Give teams a shared risk reference.

Free tools

Check a number. Understand what it means.

Heat Index Calculator Estimated WBGT Calculator UV Index Guide

Don't keep checking the forecast

Save places and get notified when heat risk changes in HeatGuard for iPhone.

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