Somebody has to measure the sky.

Where the weather comes from

Weather data from MET Norway, the Norwegian Meteorological Institute. It is published through their Locationforecast API and licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) and the Norwegian Licence for Open Government Data (NLOD 2.0).

What we changed

CC BY 4.0 asks anyone who adapts the data to say so. We adapt it, so here it is in full.

We fetch a forecast for each half-degree cell of the world that holds a radio station, and we keep two of the six fields MET publishes: the air temperature and the weather symbol code. Of the ninety hourly steps in a forecast we keep the next twenty-four, and the app reads the one for the current hour. We strip the day and night suffix from MET's symbol code and work it out again on your phone from the sun's actual position, because a forecast that was baked a few hours ago can call it night while it is still afternoon where you are listening. We draw the weather with our own icons rather than MET's. Temperatures are stored in Celsius and shown in whatever unit your region uses.

None of this changes what MET measured. It selects from it, and reformats it.

Your phone never talks to MET

The forecast is collected by a small service of ours, once, for the whole world, and published as a single file. Your phone downloads that file at most a few times a day and looks up the answer on the device. MET sees our service. They never see you, your location, or which station you tuned to. Nothing about you leaves your phone for this.

The same is true offline: once the file is on your phone, the weather keeps working with no connection at all.

Two notes on accuracy

The number is a forecast, not a thermometer reading, and it describes the cell the station sits in rather than its exact address. For most stations that point is within a few kilometres, which is finer than the weather model itself can resolve. Outside the Nordic countries the model behind it is ECMWF's global one, at roughly nine kilometres, with no local observations blended in.

If a station has no coordinate in our catalogue, or sits in a cell we have no forecast for, the card simply shows no weather rather than guessing.

Everything else

The rest of the software and data behind the app, with the full licence notices, is on the licenses page. What the app does and does not send anywhere is on the privacy page.