Explaining about day and night in the UK how?

I'm trying to tell my friend that the sun goes down very quickly in the winter in the UK. It is started to get dark at three o'clock. It is natural to say:

In the UK, it gets dark very early in winter. Three o'clock and the sky started to turn to dark blue.

or it is dawn at 3 in winter?

In summer, it is light at around two or three o'clock.