The thermometer lies.
We tell you the truth.
WetBulbTracker shows the heat your body actually has to survive — wet-bulb globe temperature, validated and live, anywhere on Earth.
Your thermometer doesn’t know if you’ll be okay.
Air temperature ignores the one thing that decides whether heat is dangerous: whether your sweat can still cool you. When humidity climbs, evaporation stalls — and the same 95° can be a pleasant dry afternoon or a medical emergency.
Wet-bulb globe temperature captures all of it at once — heat, humidity, wind, and the sun beating down — in a single honest number. It’s what the military, athletic associations, and occupational safety boards use to decide when it’s no longer safe to be out.
At a wet-bulb temperature near 35°C (95°F), a healthy person can no longer shed heat — even at rest, in the shade. That’s the line. WetBulbTracker shows you how close you are to it.
Everything you need to read the heat.
Validated WBGT
Wet-bulb globe temperature via the full Liljegren (2008) energy-balance method — the occupational and military reference standard, cross-checked against the U.S. National Weather Service.
Seamless global map
A smooth, interpolated heat field for the entire planet. Pan and zoom anywhere; tap any point for its exact reading.
Five heat lenses
Heat Stress, Real Feel, Mugginess, Heat Index and Wet Bulb — switch instantly to see heat the way that matters to you.
7-day & hourly forecast
Daily peaks and an hour-by-hour strip for the metric you care about, with the day's hottest window marked.
Plain-language AI brief
A short, time-aware read on what conditions mean right now and what's coming — written for humans, not meteorologists.
This day in history
How today ranks against the same date across 35 years of reanalysis — the normal, the record, and where today lands.
Installable & offline
Add it to your home screen. It opens instantly, works offline on your last view, and feels like a native app.
Shareable & free
Every place is a link you can send. No account, no paywall, light or dark — just the number you need.
Built for accuracy, open for scrutiny.
Best available data
Leading numerical weather models (ECMWF and national blends, via Open-Meteo) for live conditions, and ERA5 reanalysis for 35 years of history.
Rigorous physics
The full Liljegren (2008) iterative energy balance — solving for the black-globe and natural wet-bulb temperatures, not a rough approximation.
Validated & open
Cross-checked against the U.S. National Weather Service's own WBGT (agreement within about ±1.3°C). Every formula and constant is published.
If heat can hurt you, this is for you.
Athletes & coaches
Call practices and races by the standard governing bodies actually use.
Outdoor workers
Know when to add water breaks, shade, and rest — before someone goes down.
Parents & caregivers
Judge the playground, the game, the walk — for the people who feel heat hardest.
Event organizers
Plan around the day's real danger window, not just the forecast high.
Travelers
Understand a climate you've never felt before, anywhere on Earth.
Researchers & media
A transparent, validated, citable heat-stress reference with an open methodology.
Heat is the deadliest weather hazard — and it’s getting worse.
It kills more people most years than floods, hurricanes, or cold — and a warming planet pushes more places toward the survivability limit every season. The number that actually measures that danger has been locked away in safety manuals and research papers. We’re making it legible to everyone, everywhere — accurate, honest, and free.