NOAA Open Data Dissemination (NODD)
NOAA Open Data Dissemination makes the US National Oceanic and Atmospheric Administration's data freely available through major cloud platforms, so you can access it where compute already lives. The programme covers climate data records alongside atmospheric, oceanic, and terrestrial datasets.
NOAA maintains one of the largest climate data archives through the National Climatic Data Center, whose Climate Data Online service provides weather and climate data including temperature, precipitation, and station metadata. As US Government work, everything sits in the public domain.
Related sources
Copernicus (EU Earth Observation)
The EU's flagship Earth observation programme. The Copernicus Climate Change Service portal provides authoritative information about past, present, and future global climate, derived from Sentinel reference products alongside other satellite observations and in-situ measurements.
Met Office DataPoint / CEDA
The Centre for Environmental Data Analysis hosts UK atmospheric and Earth observation data, including Met Office archives, climate model outputs, and satellite data.
NASA Earthdata
The home for full and open access to NASA's Earth science data collections. The umbrella portal for the largest collection of freely available Earth science data in the world, with over 12,400 datasets spanning land, ocean, atmosphere, and cryosphere, collected by satellite missions, airborne campaigns, and ground stations.
World Resources Institute
Free environmental data for GIS, climate research, and sustainability projects. Includes Global Forest Watch and other environmental monitoring datasets.