When I do my daily check of sunset time on https://www.timeanddate.com/sun/uk/london, I appreciate that they include a chart showing how the dawn and dusk times vary throughout the year. It's important to know when to start my gloaming. Anyway, the chart they use is called a carpet plot, and some more good examples can be seen on Wikipedia's twilight page. I've included one here, of the extreme northern latitudes, where you can see that the sun never sets in the middle of the year, and it never rises around December.
It's always good to discover useful new chart types. Next I'd like to work out how to generate them myself.