Official weather warnings explained

Who issues warnings

Each country has an authority responsible for weather warnings. Examples include the National Weather Service in the United States, the India Meteorological Department and the National Disaster Management Authority in India (through the SACHET alert system), the Met Office in the United Kingdom and the Bureau of Meteorology in Australia. OLWeather shows official warnings where its providers return them and always credits the authority that issued them. OLWeather is an independent app and is not a government service.

Watch, warning and advisory

• Watch means conditions are favourable for a hazard to develop. It is time to prepare and stay alert.
• Warning means the hazard is happening or is very likely. It is time to act.
• Advisory usually means a less severe but still disruptive condition, such as dense fog or slippery roads.

The exact words differ by country, so always read the text of the warning itself.

Colour-coded warnings

Many countries use colours to show severity. Green means no warning, yellow means be aware, orange means be prepared, and red means take action because danger to life or property is likely. Check what the colours mean in your country, because the same colour can describe a different level of impact in different systems.

What to do when a warning is issued

• Read the full text: the hazard, the area and the time it applies to.
• Follow any instructions from local authorities, including evacuation orders.
• Move indoors or to higher ground if told to, and avoid flooded roads, fallen power lines and coastal edges.
• Keep a charged phone, water, medicines and a torch, and check on neighbours who may need help.
• Do not rely on a single app. Check your national authority and local radio or alerts.

Timing and delay

Warnings can be updated, extended or cancelled at any time. An app shows what the issuing authority's feed returned at the time it last loaded, so there can be a short delay. When in doubt, open the authority's own website or alert service.

What OLWeather does and does not do

OLWeather displays official warnings with their source, and separately shows its own planning guidance, which is never a safety determination. It does not replace emergency services or official guidance. For emergencies, contact your local emergency number. See also where our data comes from.