Hello. I want to compare the ERA5 data and the data i get form direct measure. In this case total water vapour.
Since the ERA5 updates daily I should download daily too, but how could i do this?
I know a little programing and I’m very new in climate data processing too so I’m sorry if this is kinda basic 
Hi Julieta,
Aș far as I am aware, the ERA5 data on Copernicus CDS is always hourly, and the data gets update about 5 days later (not every data). So you will need to aggregate the hourly data to daily values for your location (Note that the timezone is UTC in ERA5, i.e., unless your location is also in the UTC timezone, you will need to add/subtract hours to your location local time).
Another option is to access the ERA5 daily data from Google Earth Engine (GEE) and here too there will some latency (i.e., data won't be updated immediately on the next day). The advantage here is that the data is already daily (so you save the trouble of aggregating from hourly values). But GEE requires knowledge of either Javascript, python or R, where as Copernicus CDS will be easier to use with little programming knowledge. You will only need to register on Copernicus and find your way to ERA5 data, and then extract the variable for your day/time, location. The output file will be either grib or netcdf (which you can read in R, Python etc..)