Human-documented information on the weather, whether described in detail, noted in passing or measured, is one of the most important sources of climate history. Climate is understood to be the (statistical) summary of weather events at a particular location over a long period of time, i.e. thirty years or more, while people's lives follow the rhythm of the weather for a few days or weeks. Euro-Climhist makes weather and climate history data accessible with a user-friendly search, daily weather data as well as extreme events and long-term climate trends.

With their growth and shrinkage, glaciers are probably the most vivid witnesses of long-term climatic changes. The juxtaposition of the two photographs of the Rhone Glacier from 1855/56 and 2009 illustrates the profound climate change of the last 150 years, which we would otherwise not be able to see. Around 1860, the Rhone Glacier completely filled the valley plain near Gletsch with its enormous ice cake. Today, it has melted so far back that it can no longer be seen from the valley.