Features

• Living skies. Drawn, gently animated skies for every condition: sun, the moon in its real phase, stars, drifting clouds, rain and snow that lean with the wind, fog, and storms with lightning flashing inside the clouds. Sunrise and sunset colours blend with the time of day, and the sun and moon never share the sky; at twilight there is only a faint moon.
• Location screen. The next 24 hours, up to 10 days, and tiles for wind, humidity and dew point, UV, pressure with its trend, visibility, and sunrise and sunset. Swipe between saved places.
• Northern lights. Where aurora is realistically visible, a card lists the next nights with a chance meter and the best viewing window, from the Kp forecast, your location's darkness and cloud cover. Below a 50% chance it collapses to a single line, and it opens on its own when any night reaches 50%. Southern lights in the southern hemisphere.
• Widgets. Small and medium Home Screen widgets for where you are, the medium with a six-hour forecast.
• Your way. Choose which unit leads (the other is always beside it), the forecast source, animated skies everywhere, on the location screen only or off, and the list background.

How it works

The app and its widgets share one cache on your iPhone. MET Norway forecasts and the northern lights file come through duoTemp's own proxy on Cloudflare, which caches them so people nearby share one request to the source. Apple Weather fills in a place's details when you open it, and supplies every forecast if you choose it as your source.

Privacy

duoTemp has no accounts, analytics, ads or tracking, and collects nothing that identifies you.

• Your location stays on the device. Only coordinates rounded to about 1 km are sent: through duoTemp's caching proxy at api.trough.dev to MET Norway, and to Apple Weather when you open a place's details or choose Apple Weather as your source.
• The northern lights forecast is one global file; no location is sent for it.
• Saved places, settings and cached forecasts are stored on the device only.

Read the full privacy policy. For help, see support.

Data sources

• Forecasts: MET Norway (CC BY 4.0)
• Forecasts: Apple Weather
• Northern lights: GFZ Potsdam Kp forecast (CC BY 4.0)
• Northern lights fallback: NOAA SWPC

Licence

The duoTemp core is open source under the Apache License 2.0, with the source on GitHub. Premium features are separate. “duoTemp” and its icon are trademarks of David McPhearson.