The German Meteorological Service (Deutscher Wetterdienst) has historical meteorological data freely available for download on its server. Long-term trends in temperature can be visualized using for example monitoring data from the Potsdam weather station, which spans dates from 1893 to 2024.
Visualizing the trend needs some processing, as daily temperatures vary cyclically each year. This is of course the proverbial difference between weather and climate, that some people refuse to acknowledge.
The cleaned up curve show a very clear tendency towards a warming climate. The mean temperature in Potsdam (which is in a continental central European climate zone) is close to 3 degrees warmer in 2025 than in 1900.
