I read that people used to sleep much differently before electricity. Specifically, it was common for people to sleep a few hours, get up for an hour or so, and then fall back asleep for a few more hours. Part of this was chalked up to people having more time to sleep because when the sun was down, there wasn't really much to do -- people don't sleep like this anymore because we try to get it all in at once so we don't waste time at night. So, accordingly, I would imagine during the summer, when days are longer, people would have slept less and during the winter, when days are shorter, people would have slept more. Is this true?
It would be interesting to hear new answers particularly given the somewhat conflicting information given in the thread linked below, but you might be interested in this:
How accepted is the theory that most humans practiced "segmented sleep" prior to the Industrial Revolution? with an answer from u/zagreus9 and a counterpoint from u/whatthefat