The Lemon Fool

I know that there are 4380 hours of darkness in a year but how many hours of darkness in a year are there between 4pm and 1am in the UK?

or does it just average out as 9/12ths of 4380?

Not a direct answer to your question, but the raw data to provide the answer is here:-

https://www.timeanddate.com/sun/uk/belfast
( enter your chosen location, rather than mine of course )


Might need a bit of processing though...

Ah, I see 4380 is 365*24/2. This doesn't allow for twilight.