A wall of honest clocks · computed, not fetched
How long until.
Every date that actually matters, counting down on one wall — and every built-in clock is computed on this page, not fetched: the equinoxes and solstices from the astronomical series, the next full moon from the lunation arithmetic, the clock changes from the statutory rules, tax day from its real weekend logic. Astronomy is arithmetic; no feed is needed and none is used.
Add your own dates below the wall — they live in this browser and nowhere else.
The wall
The clocks everyone shares.
Soonest first. A clock under 48 hours ticks by the second; past events say NOW and stay honest about it. Each card names the rule it was computed from.
Your dates
The clocks only you keep.
A name and a moment — a deadline, a launch, a birthday, a renewal. They are stored in this browser’s own memory and never leave it.
Nothing here yet — the wall above keeps counting either way.
Method
Where each clock comes from.
The astronomy is computed here
The equinoxes and solstices use Meeus’ polynomial plus the 24-term periodic series (Astronomical Algorithms, ch. 27) — good to a couple of minutes across this millennium. The full moon uses the ch. 49 lunation series with its main solar and lunar anomaly terms — good to a few minutes. Both are corrected from astronomers’ time to civil time by the current ~69-second ΔT. After this page loads, it makes no network requests at all.
The civil rules, stated
US clock changes follow the Energy Policy Act rule (second Sunday of March, first of November, 2:00 local); the EU follows directive 2000/84/EC (last Sundays of March and October, 01:00 UTC). US tax day is April 15 moved past weekends and Washington DC’s observed Emancipation Day — the actual IRS logic. The 2038 clock counts to the second signed 32-bit Unix time runs out. Every card is drawn in your zone, named at the top of the page, because a countdown in someone else’s zone is a small lie.