Here are useful links to climate related data sources
NASA Earth Observatory and NOAA
NASA Cloud Product: Description of the tool.
AIRS data: Various data of the atmosphere
NOAA: Global Historical Climatology Network (GHCN)
NOAA Sea surface temperatures (ERSST V5)
Arctic and Antarctic climate and sea ice
Artic Sea Ice Extend for Arctic and Antarctic
Temperature.global: Online measurement and overview of global temperature
Climate Reanalyzer – Daily anomalies of global temperature etc.
DWD (Deutscher Wetterdienst): Historical Temperature measurements in Germany (1781 until present)
Climate4you: A collection of many different climate relevant data.
Creating plots from various sources: WoodForTrees
KNMI Climate Explorer (initialized for maximum Temperatures in Siberia)
Australian Buro of Meteorology, Online Climate Data
Global Carbon budget
MODTRAN Interactive Tool for OLR IR spectra and Downwelling IR spectra
HITRAN etc: Spectroscopic Data base.
The German energy transition
Agora-Energiewende: Useful information of hourly current energy mix in Germany including corresponding electricity trading prices.
Energy Chart: Actual and planned distribution of energy generation in Germany.