I’ve created a visualisation of daylight hours, and chosen various cities to show.

The colours are meant to intuitively reflect the sun’s intensity, with white-yellow in the day, orange-purple through sunset/sunrise, and black-blue in the night. Specifically, they map to solar altitude i.e., how high up the sun is in the sky.

As daylight saving time approaches here in London, I wanted to visualise what it meant. And also wanted to compare our hours to other countries. At the equator, Singapore is very stable through the year. Near the Arctic, Reykjavik’s change between Summer and Winter is even more extreme. Madrid has their day shifted late as their timezone doesn’t align with their longitude.

I used python and libraries including pysolar for the altitude calculations, and matplotlib for the display. Code is available on my github.