Belgian RMI (Royal Meteorological Institute) provides open data related to weather forecasts, observations, and climatological data here. Gridded observations are provided in monthly csv file.
Nc file are very convenient, for example for processing with cdo software. This simple code convert csv file to nc format
./irm2nc --in /home/jo/Documents/Scolyte/Data/climat_Sco/IRM/climateGrid/climategrid_202408.csv --inputGrid /home/jo/app/irmGriddedObs2nc/in/grilleIRMGDL.nc --inputGridDef /home/jo/app/irmGriddedObs2nc/in/gridIRMGDL.txt --out=/home/jo/Documents/Scolyte/Data/climat_Sco/IRM/climateGrid/test.nc
git submodule init
git submodule update
sudo apt install libnetcdf-c++4 libnetcdf-cxx-legacy-dev cdo
compilation is then performed with qmake (from Qt creator e.g.)