Don't panic Mr. Mainwaring.

I'll not make a habit of it 
BUT again I say.
It befell thusly:-
Not many days ago I happened to point out a typical "Solar Day" graph.  He pointed out that which I already knew - it depends entirely upon cloud situation.  I did, at the time wonder - (can't recall, he might) whether there'd ever be a standard (Bell) distribution curve in this climate.

By an odd coincidence there was, on Saturday.  I haven't included the entire week - boring AND cramped. BUT - what I have shown represents three from norm for this week, plus Saturday's.  NO prize for guessing which. 
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Retrospective:- 
You can, just about, make out the usable daylight starts between 03:30 & 06:00 until about 21:00 Somewhat late, I had the idea of logging it, starting here.
Next one along.