Thanks Mattk and galfert!
I really had to look up "Cocohrahs", nice with volunteers!
Yes, in "historic" times it made sense with 6AM, and reports by telephone were made at around 7 AM. But SMHI still says 6 AM makes sense because of the rain period of any day is more likely to occur evenings and nights when temperature falls. Another thing that points to this is that last days precipitation data is not available until around 10AM...
Yes and Sweden has old style manual weather stations, along with a bit better and then a new standard.
I still see all stations reporting precipitation with that skew. From what I can see in my data that skew is more of a true thing during summer half year. But that is only data from my station.
Also, I think that in any country using DST the don´t use the DST midnight, but rather keep to the normal? I was recommended by an American professor in meteorology to keep the Standard time on my ws. This because days when DST et c occurs is not on the same dates, which makes comparisons between dates more problematic. I even do comparisons "days after winter solstice", "days after spring equinox", ... since where I live, N 63.8 E 15.9, we have a swing of -31C to +31C and every day in theory should count for a change of 0.339C per day, and I study the inertia of temperatures. The graph is an example of such an offset from from Winter Solstice . There is a tiny hand written red line that shows we first loose max temps and then the average of max'es, average, and so on.