Severe Weather API

The Severe Weather API provides information on adverse and severe weather conditions forecast for any location worldwide. All information is provided in GeoJSON format making the affected areas simple to visualize on maps or to use as part of other location-based services. Active severe weather alerts can also be requested for any point location by using them as an extension to the Vaisala Weather API.

How it works?

The API creates alerts when there are severe weather events detected in the forecast for the area in question. A severe weather event means the weather is not typical for a certain area, or it is exceptionally intense in relation to the normal weather conditions in the area.

The service covers the following severe weather Events:

  • Abnormally cold / hot temperature
  • Blizzard
  • Freezing rain
  • Hail
  • Heavy rain
  • Snowfall
  • Strong wind
  • Thunderstorm

Locally adjusted event significance levels

The significance of weather phenomena is classified by using color codes (yellow, orange, red) which are in relation to possible harmfulness for people and property. Severe Weather events are defined by differing thresholds taking into consideration what is normal, rare, exceptional or harmful weather in different countries and areas worldwide.

  • Yellow - Severe weather advisory: Be aware and stay informed with local weather information and governmental warnings.
  • Orange - Severe weather alert: Be prepared and reconsider your outdoor and travelling plans. Stay informed with local weather information and governmental warnings.
  • Red - Extreme weather alert: Take action to keep safe and weatherproof your property. Stay informed with local weather information and governmental warnings.

The service can be used to inform people about severe weather events during the upcoming hours and days.


The API returns the following information based on forecasts:

  • Severe weather event type (parameter)
  • Start time for the event
  • End time for the event
  • Event significance level: yellow, orange, red
  • The affected geographical area given as MultiPolygon (in GeoJSON feed)
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Key Benefits

Geographical accuracy
Severe Weather API provides alerts for local areas whereas governmental warnings are usually given for whole administrative regions even if an issue is likely to have an impact only for a small part of that area.
The start and end time of an event is based on exact forecast time frame whereas governmental warnings are usually issued for a default period, such as one day at a time.
Geographical coverage
The service has worldwide coverage via one simple interface whereas national weather warnings need to be sourced country-by-country.