Frequently Asked Questions

Please note: The Weathermuffin app has been sunset as of November 2023 and is no longer available.

Q. What is Weathermuffin?

A novel weather app developed specifically for cruisers, by a fellow cruiser. Based on your specific position, course, and speed, it watches the forecasts to warn you of potentially hazardous or uncomfortable conditions ahead.

Q. How does Weathermuffin differ from Windy or PredictWind?

Weathermuffin is different by design—you won’t find any GRiB files here. Here’s how Weathermuffin is unique:

✅ It monitors your conditions ahead.

When you use Weathermuffin, your current position, course, and speed are used to examine the conditions around you and the forecasts ahead for the next 72 hours. You’ll see a list of potentially hazardous or uncomfortable conditions to be on the lookout for. You’ll see the areas of hazard on the map, in the context of your position, so you can plan to evade or prepare. Plus, even handier, you can “slide” time forward and back to see forecasts in context with your extrapolated future position (given course and speed are maintained).

The full list of conditions monitored can be found here, but beyond the basics like wind speed and wave height, includes the conditions sailors care about most, like steep waves, wind opposing current, lightning strikes, and more (with new monitored conditions being added continually).

“The steepness of the waves is often of far greater interest to the seaman than the mere heights of the waves.”

Graham P. Britton, Captain, Royal Navy (Retired) – source

✅ It gives you synoptic charts.

Synoptic charts are weather charts produced by the professional meteorologists at NOAA. As such, they depict fronts and other weather features not shown on GRiB files. Synoptic charts are shown on a map in context with your current position. And of course, as above, you can “slide” time to see the forecasts in context with your extrapolated position.

Q. Can I trust Weathermuffin?

Weathermuffin uses the same weather data sources you already know and trust… products built by the professionals at NOAA and cutting-edge weather models like GFS. Weathermuffin is looking at the same GRiBs you are.

As for your personal data, Weathermuffin’s servers are located in the United States, and the app does not collect your personal information. See our privacy policy for more information.

Q. Does Weathermuffin replace Windy, PredictWind, etc.?

No. You still need another service if you want to view GRiBs and do weather routing. Further, considering the importance of the weather to sailors, cruisers, and other mariners, it doesn’t hurt to have multiple sources of weather information. Just be sure to understand the unique strengths and limitations of each source.

Q. What is required to use Weathermuffin?

  • An iPhone or iPad. (Sorry, it’s not available on Android yet!)
  • An internet connection. This can be Iridium GO, Starlink (or other satellite broadband), or cellular/wifi (when within range, of course).

Still have a question?

Email us at and we’ll be happy to help!