Find warning guidance for your country
Every country radar page includes a warning-level section. Use the Official warnings directory to jump to it. Agency-specific and regional explanations are distinguished from international severity terminology; where a national scale has not been verified, the page says so. No example card represents an active warning.
The Netherlands: KNMI warning colours
KNMI issues regional warnings, so different areas can have different codes. Its colours describe the expected impact of dangerous weather, not simply how dramatic a thunderstorm looks. Yellow, orange and red also apply to hazards other than thunderstorms. Always check which weather phenomenon the warning names.
What should I do during a Dutch thunderstorm warning?
For thunderstorms, KNMI advises going indoors and avoiding trees, open fields and open water. With code orange, postpone travel if possible and do not go out on the water. With code red, stay indoors. Read the latest local message for further instructions; the colour alone does not describe every risk.
Why orange does not automatically turn red at one wind speed
KNMI considers expected impact when issuing warnings. Code red is not simply an additional wind-speed band above orange. Location, exposure and the potential for disruption matter. Do not calculate your own warning colour from one value on a weather map.
United Kingdom: yellow, amber and red
The Met Office combines the likelihood of impacts with their potential severity. Yellow and amber can each represent several combinations of likelihood and impact. Read the warning details to understand what is expected where you are. A UK amber warning and Dutch code orange share a colour family, but should not be treated as identical criteria.
United States: watch, warning and damage threats
US severe thunderstorm alerts use named products rather than the Dutch colour-code sequence. A watch calls for preparation; a warning calls for protective action. Within Severe Thunderstorm Warnings, base, considerable and destructive describe damage threats. None is a direct translation of KNMI yellow, orange or red.
India: moderate describes a different type of category
IMD nowcast documentation includes moderate, severe and very severe thunderstorm categories based on surface wind gusts. That terminology is not the same as a Dutch warning colour or a UK impact category. Our moderate thunderstorm warning guide explains the specific IMD ranges and how to read the original message.
Rain-radar colours are not warning levels
A yellow or red patch on a rain map belongs to that map’s precipitation legend. It does not mean that an official code yellow or code red warning has been issued. The same applies to storm-cell colours: read the provider’s legend, then check the national weather service separately for official warnings.
No warning is not a promise of no danger
A warning applies to a particular area, time and hazard. If thunder is audible, take lightning shelter even if no warning is shown for you. Do not wait for a colour to change before acting on nearby thunder or local emergency instructions.
A practical way to compare warnings when travelling
Keep the original country and agency name with the warning. Check the valid period and your exact destination, then read the action advice. Do not convert an unfamiliar label to a colour you know from home. Bookmark the official service before departure so it is easy to find an updated message.
International severity terms: only when the alert uses them
Some official alerts include Common Alerting Protocol severity terms: Minor, Moderate, Severe, Extreme or Unknown. These describe the stated threat; they do not prescribe a worldwide colour scheme. Unknown means the severity is unspecified, not that no hazard exists. Read urgency, certainty and the actual safety instructions as well.
Sources & further reading
View the references for this guide
Editorial review: 25 September 2026. Map measurements are updated separately by the provider.