Show HN: The current sky at your approximate location, as a CSS gradient
259 dlazaro 53 8/9/2025, 1:25:16 PM sky.dlazaro.ca ↗
For HTML Day 2025 [1], I made a web service that displays the current sky at your approximate location as a CSS gradient. Colours are simulated on-demand using atmospheric absorption and scattering coefficients. Updates every minute, without the use of client-side JavaScript.
Source code and additional information is available on GitHub: https://github.com/dnlzro/horizon
Well, the higher ups of course hated it, they were confused as to why the horizon would get hazy, yellowish, and so on. "Our competitors' skies are blue!" They didn't like "Use your eyes and look outside" as an answer.
Eventually, I was told to scrap it and just draw a blue rectangle :(
All that to say, nice job on the site!
1: https://courses.cs.duke.edu/cps124/fall01/resources/p91-pree...
I can understand people removing polish things like that if there are usability concerns, but those small things add up to a lot in an end product and are a joy to find and explore.
1: https://en.wikipedia.org/wiki/Cobalt_(video_game)
If you're the kind of developer who likes to "sand and finish the back side of the cabinet," either you need to find a very rare, special company, or do it at home as a hobby.
You could've sold it with telling them Vincent Van Gogh's paintings had the location of stars accurately, you were inspired by those paintings to reproduce the sky color accurately.
Oh, don't mind me, I'll just be over here in the corner laughing ruefully as my bones crumble to dust: back when I started, if you wanted a page to refresh on its own, this was the only way.
Beautiful work! A splendid example of formal minimalism at its best.
what got me the most is opening chrome dev tools and seeing nothing there
I wonder what it would take to account for weather?
(I used this, but it does leave a small "please purchase" banner at the top, until you pay: https://play.google.com/store/apps/details?id=com.nuko.livew...)
- First and most impactful: as the earth curves down and away from the observer's horizon, your line of sight goes through a thicker slice of the atmosphere.
Looking straight up you might have 100km of atmosphere until space (the distance is made up here, but I'm using the Kármán line as an arbitrary ruler), but looking out towards the horizon (assuming a perfectly spherical Earth), it's much, much more than that 100km, so the light will scatter off of (and/or be filtered by, depending on angle and time of day) more particles in the atmosphere, affecting the colour of the sky.
- The compounding factor here is if there are environmental factors that boost the particle count in the air, and especially particles that'd stay in lower layers of the atmosphere. Where I am, we've been dealing with wildfire smoke of varying strengths for a few weeks. Today's gentle enough, but it's bad enough that my gradient goes from rgb(115, 160, 207) at the top of the sky to rgb(227, 230, 227) at the horizon (which is shockingly accurate).