Knowing the heat is free. Always.
Every reading, every warning and every piece of guidance on this site is free and stays free. What the paid plans add is reach: further ahead and further back, finer control over when and how you are warned, exports and records you can hand to somebody else, and — for an organization — every site you are responsible for in one place.
Free
- Live heat-stress readings anywhere on Earth
- Plain-language guidance and safety warnings
- A written outlook for the day, in plain English
- Six ways to read the heat, with rain and pavement overlays
- Animate the map through the next 24 hours
- Sun and shade, pavement and paw safety
- “Safe for me” personal risk, on the card and on your alerts
- Heat alerts a day ahead, with overnight quiet hours
- Seven days of daily highs, and today’s report
- Share as a link, or export a PNG or PDF
- Viewing any report someone shares with you
- Three saved places and three heat alerts
- 35 years of this-day-in-history
- State athletic-policy tables for high-school sport
- City guides, the calculator, and the full methodology
- Export everything in your account, any time
Plus
Everything in Free, plus:
Pro
Everything in Plus, plus:
What we will never put behind a payment
Someone in danger from heat should never meet a paywall, and neither should the person they sent the reading to. So these are the things we have committed to keeping free — not “free for now”, but free as a rule built into the product, where it cannot quietly slip while nobody is looking. Much more than this is free today. These are the parts we are promising will stay that way.
- Current readings, anywhere
- Guidance and safety warnings
- Your personal risk profile
- City guides
- Viewing a report someone shared
- Today's heat report
6 capabilities, free at every tier including no account at all. Viewing a shared report never asks anyone to sign in.
The fine print, up front
Cancel yourself, any time. Canceling is a button in your account, not an email to us. You keep what you paid for until the end of the period you already bought.
What Pro documents are, and are not. Pro produces a dated, sourced record of what the conditions were and how they were computed, something an organization’s own record-keeping can cite. It is not a substitute for an on-site instrument where a standard, contract or policy requires a measured reading, and it does not certify that anyone has met any obligation.
Our numbers are modeled. WBGT is computed from gridded weather by the Liljegren (2008) method and, where a learned correction clears its held-out check, corrected against the National Weather Service’s own published WBGT, which is itself a model. We publish how well it does, in public, on the live accuracy page.
Informational only. Not a guarantee of safety, and not a substitute for official heat warnings or medical advice. Always follow your local authorities and your weather service.