The weather turns. The call stays yours.
GRAT reads the weather risk for the point you are standing on and the altitude you are at — then gets out of the way.
Download on the App Store
- iPhone & Apple Watch
- Free
- No account
- No ads
- No tracking
One verdict, and why
Safe, Watch or Danger — never on its own. Always with the reason behind it and the model or service that produced it.
Summer brings thunderstorms; the cold months bring gusts, ice and cloud. The level weighs all of it against your altitude and your route grade (T1–T6).
Thunderstorms
Lightning potential, unstable air and showers in the coming hours.
Gusts
Expected gusts, estimated higher on a ridge or a steep slope.
Freezing level
Near or above the 0 °C line, icing counts too.
Visibility
When it drops, losing the route gets easy.
Cold and wet
Feels-like temperature, together with rain and wind.
Falling pressure
A fast drop can mean a front is on its way.
Most weather apps always show you something. This one stops.
When the radar, the lightning network or the official warning is missing for where you are, GRAT says so. Missing data is not missing risk, and a green screen you cannot trust is worse than no screen at all.
A typical weather app
Safe
Green and confident, from a forecast grid that has nothing for your valley.
GRAT
Cannot be evaluated
No lightning data for this cell. Here is what is missing, and what we do have.
Radar with its gaps marked
Live precipitation with a time scrubber. Where the radar has no coverage the map stays grey and the legend says why.
DWD in Germany, RainViewer and NOAA elsewhere.
Companion Mode walks with you
Start it at the trailhead. The risk is re-read every 15–20 minutes as you climb, and you get a notification if it rises.
No alerts while the app is closed — we say so plainly.
The call, on your wrist
The watch never computes risk itself. It shows what your iPhone decided, together with how old that reading is.
A second risk engine would mean two screens that can disagree.
Free and Pro
The risk level, official warnings and radar are always free. Pro adds the convenience around them.
| Feature | Free | Pro |
|---|---|---|
| Risk level, official warnings, radar | Yes | Yes |
| Companion Mode | 2 sessions / month | Unlimited |
| Offline route forecasts | No | Yes |
| Full history with CSV export | No | Yes |
| Live Activity | No | Yes |
- Pro, yearly€24.99First 14 days free
- Pro, monthly€3.99
- Pro, for life€49.99Launch price until 21 January 2027, then €69.99
Built by one person who walks these routes.
Not a weather portal with a mountain skin: every threshold, and every refusal to guess, is a decision someone made and will answer for. Each month we publish how the alerts actually did — the hits, the false alarms and the misses.
The sky turns fast up there.
Download on the App Store
- iPhone & Apple Watch
- Free
- No account
- No ads
- No tracking
Available in the European Union, including Germany and Austria, along with the United Kingdom, Switzerland, Norway, Türkiye, the United States, Canada and Australia.
