Where the numbers come from
The data behind every forecast on this site and in the app, and its licences.
The forecast
Weather data by Open-Meteo.com
CC BY 4.0
Open-Meteo weather data
CC BY-SA 4.0
UK Met Office forecasts, which Open-Meteo uses for the first days at UK places
Licence to Use Copernicus Products
Contains modified Copernicus Atmosphere Monitoring Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.
UVA is worked out by Solarpunk from the forecast solar radiation and the sun's height; it is not measured. The face figures are a rough figure for the share reaching a face.
Where the counties and regions come from
Contains OS data © Crown copyright and database right 2026.
Source: Office for National Statistics licensed under the Open Government Licence v.3.0.
Contains OS data © Crown copyright and database right 2025.
Contains public sector information licensed under the Open Government Licence v3.0 (© Ordnance Survey of Northern Ireland).
Place names
The maps
Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com.
How UVA is worked out
The UVA model was calibrated against data obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's POWER Project, funded through the NASA Earth Science Division's Applied Sciences Program.
The UV Index doesn't measure UVA.
It measures the sunlight that burns, mostly UVB. We created an app that shows both, so you know when to wear sunscreen.
Free for iPhone, worldwide. Android coming soon.