@Korina The two time series are shifted by one hour because the stations are in different time zones: the value at time H in 1f06c9a6f matches time H+1 in f06c9a6f. But apart from that they are identical, to convince you have a look at the original netatmo data coming from Salford:
And compare it with the data shown on windy:
Clearly they are not the same, but if you compare the latter with f06c9a6f (shifted by one hour) they are the same.
I've now deleted and recreated the station, we can see in 24 hours if this resolved the problem...