GRAT: Mountain Storm Weather

Storm risk on the ridge, live

Free · Designed for iPhone. Not verified for macOS.

See storm, gust and cold risk in the mountains at a glance. Every feature is free during early access. GRAT is a decision-support tool for mountaineers and hikers. It combines official weather warnings, high-resolution weather models and station measurements into one risk level for your position and altitude: Safe, Watch, Danger. WHAT GRAT SHOWS • Shower and thunderstorm risk: at what time, and according to which model • Wind gusts and feels-like temperature (hypothermia risk) • Official warnings (DWD in Germany, MeteoAlarm across Europe) • Radar map (DWD in Germany, RainViewer elsewhere) • Pressure trend from your iPhone's barometer COMPANION MODE Start it before you set out. GRAT re-evaluates the risk regularly along the way and notifies you when it rises. Distance and barometer measurements pause automatically while you drive. At the end of the trip you can mark whether the alerts were accurate. TO BE HONEST • GRAT does not make decisions for you. Your own observation and experience always come first. • Without data, the app does not say "safe"; it says "cannot be evaluated". • If the app has been closed, it cannot send alerts. PRIVACY No account, no ads, no tracking. Your location goes to weather services only after being rounded to about 110 meters. The only thing that reaches us is what you choose to send us. EARLY ACCESS The risk level, official warnings, radar and two Companion Mode trips per month will always stay free. Unlimited Companion Mode, offline route forecasts, full session history and the Live Activity will later be part of GRAT Pro; during early access they are free for everyone too. Early users will be able to get yearly Pro at a discounted founder price when sales start.

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The developer, Bahadır CETIN, 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.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    The developer indicated that this app supports the following accessibility features. Learn More

    • Supported Features

      • Larger Text

      • Dark Interface

      • Differentiate Without Color Alone

      • Sufficient Contrast

      • Reduced Motion

    For more information, visit the developer’s accessibility website .

    Information

    Seller
    Bahadır CETIN
    Size
    5.3 MB
    Category
    Weather
    Compatibility
    Requires iOS 18.0 or later.
    • iPhone
      Requires iOS 18.0 or later.
    • Mac
      Requires macOS 15.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 2.0 or later.
    • Apple Watch
      Requires watchOS 11.0 or later.
    Location
    This app may use your location even when it isn’t open, which can decrease device battery life.
    Languages
    English and 2 more
    • English, German, Turkish
    Age Rating
    9+
    Copyright
    © 2026 Bahadır Çetin
  • Developer Website
  • Privacy Policy