Heat index & WBGT · iPhone

Know how hot it really is before you step outside.

The heat index and the WBGT for the spot you are standing on, hour by hour — with an alert 30 minutes before the day crosses your line. Every number is computed on your phone from Apple Weather. No account, no ads.

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Comfortable Caution Extreme caution Danger Extreme danger

The Today tab in Phoenix: an 87 degree heat index on the Caution flag, 84 degree air with humidity adding 3 degrees, and a 24-hour bar timeline with a Now marker. — **Today**Heat index or WBGT for right now, and the whole day as a timeline.

The Heat Risk panel: humidity, sun strength, air temperature and wind cooling bars, plus tiles for air temp, UV index, heat index, wet bulb, humidity, dew point, wind, sunrise and sunset. — **Heat risk**What is actually driving it — humidity, sun, air temp, wind cooling.

The Week tab charting seven days of WBGT with each hour dotted by flag colour, a warning about seven days in a row at High Risk, and a per-day row showing each day's peak. — **Week ahead**Seven days of peaks, hour by hour, on either scale.

The Alerts tab with Heat Alerts armed, a note that the next alert is in 3 hours as WBGT reaches 88 degrees at 1 PM, and a Morning Brief sent at 5:30 AM. — **Alerts & morning brief**Warned 30 minutes before your line, plus one summary at dawn.

The Locations sheet listing Portland, which follows you, and Phoenix, with an Add a location button. — **Locations**Where you are, and the sites you care about, watched separately.

Home Screen widgets showing Phoenix at 94 degrees Extreme Caution and Portland at 68 degrees Comfortable, a chart widget peaking at 111 degrees at 6pm, and five Siri questions. — **Widgets & Siri**On your Home Screen, or just ask — "is it safe to work outside?"

Know before you step outside.

Heat index and WBGT for your exact spot, hour by hour, with an alert before the day crosses your line.

Download on the App Store