There's a good list of weather data sources on this excellent website created by Robin Wilson, which I duplicate here in case that site ever goes away:
WorldClim: Climate data for past, present and predicted future conditions. Includes temperature (min, max, mean) and precipitation. 1km x 1km resolution.
NCAR GIS Climate Change Scenarios: Lots of data from ...
UTC (Coordinated Universal Time) is the only way that makes sense for a global dataset. Using local timezones would be an absolute nightmare for exactly this reason.
I found several references to UTC in the ERA5 data documentation.
'time' in analyses
Each analysis has a validity time, i.e. the time the data values refer to (not the time when the ...
Finally I found some useful links for station-based data for period 1981-2010:
data for Austria:
data for Germany:
data for switzerland: