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FAQ

Does it work outside Germany?​

Only in a band near the German border. DWD's radar composites cover Germany and some area around it; elsewhere the files have no data. See Grid cell lookup.

Do I need an API key or account?​

No. The data comes from DWD Open Data, which is free and needs no registration.

How much data does it download?​

About 1 GB a day on average: measured over three days in October 2026, an installation downloaded about 0.9 GB a day. It depends on the weather, and not only at your location: DWD's files cover all of Germany, and rain anywhere makes them larger, so a dry day costs less and a day of widespread rain more.

Most of it is the RV archive, read completely every 5 minutes. RS is read partially (about a fifth of each archive), and HymecNG and the RADOLAN files are small. Keep it in mind on a metered connection.

Why does "now" lag a few minutes?​

A value describes DWD's window, which ends at the release time, and DWD publishes a few minutes after that. Precipitation intensity now is about 4 to 10 minutes old by the time you see it. See Release timing.

Which sensor should I use for rain statistics?​

Precipitation total. It only ever grows, so Home Assistant's statistics, the statistics graph card and the Utility Meter helper can sum it over any period. The other sensors are snapshots of a window and do not add up over time.

What is the difference between "last 60 min" and "previous hour"?​

Precipitation last 60 min is radar only, a rolling hour updated every 5 minutes. Precipitation previous hour is the last full clock hour, corrected with rain gauges, available about 30 minutes after the hour ends. The first is faster, the second more accurate. See RADOLAN RW and SF.

Why does it rain here, but the sensor says 0?​

  • The value may not have arrived yet: radar values are a few minutes old, gauge-adjusted ones about half an hour.
  • The radar measures in the air above a 1 km cell. Light drizzle, or a shower at the edge of your cell, can be below what it detects.
  • Precipitation last 60 min and Precipitation previous hour are totals: a short shower might add only a few tenths of a millimetre.

Why does "Precipitation end" keep changing?​

With the default The first dry break, it reports the end of the current shower, which moves as showers form and dissolve. The option "Precipitation end" shows can be set to When no more rain is forecast for a steadier answer. See RADVOR RV nowcast.

Why is "Precipitation start" unknown?​

No rain is forecast within the next two hours, which is as far as DWD's nowcast reaches. Precipitation expected is then off.

Can I use it for several locations?​

Yes: add the integration once per location. See Configuration.

Is it an official DWD integration?​

No. It is a community project, not affiliated with or endorsed by the Deutscher Wetterdienst. It uses DWD's public data under their terms of use.