Short answer. German authorities warn through the NINA app, radio, TV, Cell Broadcast text alerts sent to every phone in the area, sirens, loudspeaker vans and digital signs 12. A siren's 1-minute rising and falling tone means danger: turn on the radio or check your warning app. A 1-minute continuous tone means all clear 1. A nationwide test day is held on the second Thursday of September 4.
What do the sirens mean in Germany?
The BBK defines two siren signals 1:
| Signal | Meaning |
|---|---|
| 1 minute rising and falling tone ("Heulton") | Danger: seek information — turn on the radio, check your warning app |
| 1 minute continuous tone ("Dauerton") | All clear: the danger is over |
A siren does not tell you what the danger is. It tells you to look for the official message on another channel 1.
How does Cell Broadcast work?
Cell Broadcast has been used in Germany since 23 February 2023 2. It sends a text alert to every phone in the affected area. It is anonymous, text only and needs no app 2. To receive it, your phone must run Android 11 or later, or iOS 16.1 or later, be switched on and not be in airplane mode 2.
What is the NINA app?
NINA (Notfall-Informations- und Nachrichten-App des Bundes) is the federal warning app published by the BBK 3. It includes weather warnings from the German Weather Service (DWD), flood information and, since July 2025, police warnings 3. Alerts only reach you if you subscribe to places or enable location in the app 3. The NINA helpdesk is free from within Germany on 0800 664 711 9 3.
Install it on every phone in the household: the BBK checklist lists a warning app such as NINA as part of household preparation 5. NINA is also where the federal government plans to show future public refuges; see our Germany public shelters page. Official warnings can also be read on the warnings portal, warnung.bund.de/meldungen.
What other channels carry warnings?
Radio and TV remain core channels, together with loudspeaker vans and digital signs 1. Do not rely on your phone alone: the BBK lists a solar, battery or crank radio with batteries in the household supply 5. See our Germany emergency supplies page.
When is the national warning test day?
The Bundesweiter Warntag is held on the second Thursday of September 4. It was last held on 10 September 2026, with a test warning at about 11:00 and the all clear at about 11:45 4. The next one is on 9 September 2027 4. Use it to check that your phone, app settings and radio actually receive alerts.
What should you do when you receive a warning?
Read or listen to the full message and follow the instructions of the authorities. If you are told to stay indoors, go to the place you chose in advance; see Shelter in place or evacuate after a nuclear emergency?. Agree in advance how your household will regroup; see How do I make a family emergency plan?.
Frequently asked questions
Do I need an app to receive Cell Broadcast alerts?
No. Cell Broadcast needs no app; it reaches phones on Android 11+ or iOS 16.1+ that are switched on and not in airplane mode 2.
Why did I not receive a NINA alert?
NINA only sends alerts for places you have subscribed to, or for your location if you have enabled it 3.
What does a 1-minute continuous siren tone mean?
It is the all-clear signal: the danger is over 1.
Is there a siren test in Germany?
Yes. The nationwide Warntag tests all channels on the second Thursday of September; the next is on 9 September 2027 4.
Sources
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) — Vorsorgen für Krisen und Katastrophen (2. Auflage, Stand 11/2025) — https://www.bbk.bund.de/SharedDocs/Downloads/DE/Mediathek/Publikationen/Buergerinformationen/Ratgeber/BBK-Vorsorgen-fuer-Krisen-und-Katastrophen.pdf?__blob=publicationFile&v=44 (accessed 2026-10-20)
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) — Cell Broadcast — https://www.bbk.bund.de/DE/Warnung-Vorsorge/Warnung-in-Deutschland/So-werden-Sie-gewarnt/Cell-Broadcast/cell-broadcast_node.html (accessed 2026-10-20)
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) — Warn-App NINA — https://www.bbk.bund.de/DE/Warnung-Vorsorge/Warn-App-NINA/warn-app-nina_node.html (accessed 2026-10-20)
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) — Bundesweiter Warntag — https://www.bbk.bund.de/DE/Warnung-Vorsorge/Bundesweiter-Warntag/bundesweiter-warntag_node.html (accessed 2026-10-20)
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) — Checklisten zur Vorsorge – Krisen und Katastrophen — https://www.bbk.bund.de/SharedDocs/Downloads/DE/Mediathek/Publikationen/Buergerinformationen/Ratgeber/Checklisten-zur-Vorsorge-Krisen-und-Katastrophen.pdf?__blob=publicationFile&v=19 (accessed 2026-10-20)
Turn this into action
Your plan for Germany, worked out for your household.
- Water, food and equipment counted for each person and pet
- The nuclear plants and zones around your home
- Phaenyx Safe: one tap to tell your people you are safe
Sources
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) · Vorsorgen für Krisen und Katastrophen (2. Auflage, Stand 11/2025) checked 2026-10-20
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) · Cell Broadcast checked 2026-10-20
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) · Warn-App NINA checked 2026-10-20
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) · Bundesweiter Warntag checked 2026-10-20
- Bundesamt für Bevölkerungsschutz und Katastrophenhilfe (BBK) · Checklisten zur Vorsorge – Krisen und Katastrophen checked 2026-10-20