TAVG field from French meteorological stations in GSN network.
Mont Aigoual daily data is very sparse before 1982. It shows a similar recent plateau. It was omitted for compactness of the graph since it is a high elevation station and several degrees cooler
All records were filtered using a low-pass Lanczos filter to remove the annual cycle.
Script and desciption of Lanczos filter:
The only warming in these records is between 1985-1995.