probably a webcam

i presume you're on mobile and it's not visible there. on desktop you can hover any section and you will see the picture that is used as the source.

On mobile (i use firefox an android) you can tap on the sections

Tap on mobile

The first two night photos have logos for EarthCam, Live, and some location data. Seems they found a way to remove those in later images.

It appears that the camera provider was switched around 1 day ago [0].

[0] https://twitter.com/mikebodge/status/1666541169273372672

The author is a designer who do many creative coding projects, he mentioned in an interview[1] back in 2011 that:

> I wrote this program that hooks up to a webcam. It takes a photo out the window every five minutes, and it will upload that to a server. The server then reads the sky portion of the photo, and it goes pixel by pixel. What it does is it takes all those values, the RGB values, and it averages them. So what you are seeing is not the dominant color in the sky it’s actually just the average color.

Mike Bodge's personal website:https://bod.ge/

Recent tweet by author: https://twitter.com/mikebodge/status/1666507978663690240

Here's also a submission from a decade ago (2011): https://news.ycombinator.com/item?id=2685621

Shameless plug: Assisted by my HNRelevant browser extension

[1] https://www.villagevoice.com/2011/06/23/mike-bodge-nskyc-cre...

Average how? In RBG? HSL? LAB?

Average raw RGB gives you bad results.

Well, I'm afraid I can't help you with that

If you're enthusiastic about the project, maybe consider DMing the author on Twitter to discuss it with him