Cumulus Support

I've recently installed CumulusMX for the first time and am struggling to understand Sun Hours.

I have left the default settings for Solar, and checked latitude and longitude are correctly set. In my monthly log entries I see sun hours reported for logging intervals (every 15 minutes to match my station) when there is zero solar radiation and indeed during hours of complete darkness! Can anyone explain what's going on please?

Secondly, the total sun hours reported for four consecutive logging intervals (when there is non-zero solar radiation) is often greater than 1. Can I take it that the number reported in the log under Sun Hours for each entry is a decimal fraction of 15 minutes?

What do you expect to see ?

Sun hours is just that. The total number of sunshine hours that meteorological day upto that log point.

Very many thanks - that explains all!

To answer the question posed by beteljuice, as a new user I 'expect(ed) to see' the column headed Sun Hours show the sunshine in the logging interval, not a cumulative figure. The rainfall is reported as 'Rainfall so far', making clear it's cumulative. For consistency, perhaps the sunshine column would be better labelled 'Sun Hours so far'. The cumulative nature would probably have dawned upon me though had I waited until I had more data!