Heat Index: Get Heat Alerts
Feels Like Temp, WBGT & Risk
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
How dangerous is the heat right now — and when will it be safe? Heat Index answers that the moment you open it, with the same number your local forecasters use.
THE NUMBER YOU CAN TRUST
We compute the official NWS heat index — the real "feels like" combining heat and humidity — using the published National Weather Service formula, from Apple Weather data. Every reading shows its source, observation time, and location, so you can check our work. No mystery numbers, no forecast pretending to be current conditions.
NEVER A BLANK SCREEN
Lost signal on a remote worksite? The app keeps your last reading with a clear timestamp instead of an error page. Built for the exact moment other heat apps fail: the hottest day of the year.
KNOW WHEN IT'S SAFE
• A color-coded risk level with plain-language guidance — from "normal precautions" to "avoid outdoor exertion"
• An hourly danger timeline that spots your next safe window: "Safe for exertion after 7 PM"
• A daily outlook to plan work, training, and family time around the heat
SUN OR SHADE — YOUR REAL CONDITIONS
The standard heat index assumes shade. Working or training in direct sun can feel up to 15°F hotter. Flip to Full Sun mode and the number adjusts using sun angle and cloud cover.
ALERTS BEFORE IT GETS DANGEROUS
• Official government heat warnings for your saved locations
• Your own threshold: "tell me when the heat index passes 100°" — set it to match your company's heat policy or your doctor's advice
• An optional morning briefing: today's peak, risk level, and when it hits
BUILT FOR PEOPLE WHO WORK AND TRAIN OUTDOORS
Estimated WBGT (wet bulb globe temperature) with standard activity flags for athletes, coaches, and safety managers — honestly labeled as an estimate, computed correctly. Plus a plain-English heat illness guide: symptoms, first aid, and work/rest guidance you can read offline.
WORKS ANYWHERE IN THE WORLD
US, UK, Australia, Canada — anywhere Apple Weather reaches. Search any city or postcode, or enter exact coordinates for remote sites. No location permission required.
PRIVATE BY DESIGN
No accounts. No ads. No tracking. Your location never leaves your device except to fetch weather from Apple Weather. Ever.
FREE VS PRO
The current heat index, risk level, hourly outlook, government alerts, sun mode, a personal threshold alert, and the safety guide are free — the core reading is never paywalled. Heat Index Pro adds the full 48-hour timeline, 7-day outlook, estimated WBGT, up to 10 saved locations with per-location alerts, and the morning briefing.
Pro is an auto-renewing subscription (monthly or yearly, with a free trial on the yearly plan). Payment is charged to your Apple Account, and subscriptions renew automatically unless cancelled at least 24 hours before the end of the period. Manage or cancel anytime in Settings.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://trcoapps.com/privacy
Weather data provided by Apple Weather.
Ratings & Reviews
The developer, Timothy Richardson, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Timothy Richardson
- Size
- 2.4 MB
- Category
- Weather
- Compatibility
Requires iOS 17.6 or later.
- iPhone
Requires iOS 17.6 or later. - Mac
Requires macOS 14.6 or later and a Mac with Apple M1 chip or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- HeatIndex Pro Monthly $4.99
- HeatIndex Pro Annual $29.99
- Copyright
- © 2026 Timothy Richardson