Stats from XEMA per day use UTC timezones, instead of local CET

[jmones]

Stats from XEMA per day use UTC timezones, instead of local CET. This means that metereological statistics could be slightly off (1-2h attributed to the wrong day).

This should better be solved server side (SODA, Socrata API) but not sure how to do it. Asked SO:
https://stackoverflow.com/questions/61143734/date-trunc-ymd-in-cet-timezone-from-floating-timestamp-in-utc-using-soql-throu