You started Cumulus up just after midnight and it failed to do the rollover, so you are still accumulating yesterday's data (yesterday and today are combined into one day). This is one of the many bugs that have been fixed in the 18 months since the version of Cumulus you are using was released.
zehelmer wrote:Just a small additional question: how to fix the error announced at startup, concerning the relative/absolute pressure reading?
EWUSB: Read pressure values: rel=2178,0 abs=1001,3
EWUSB: Ignoring dubious relative pressure reading, using offset of zero
You need to set the relative pressure in your station, it's currently reading an impossible value. It's in the manual, but I think it's something like: press the pressure area three times, then use the + and - buttons to set the correct value. You need to find a local source for a reference value, and preferably do it on a day when the pressure is stable, e.g. a large area of high pressure.