One day across the page, from midnight to midnight in London. The band is that city's own sky, hour by hour; the bracket is nine to five in its own clock; the line is now.
The zone and its changes from the IANA tables the browser carries · the light computed for 51.51° N, 0.13° W · refreshed nightly · 2026-09-15 02:14 UTC.
How it knows
Every time here is read from the zone tables the browser itself carries — the IANA database by its zone id (America/Los_Angeles, not "Pacific"), through the browser's own Intl — never from an offset typed in by hand. A zone's name is what those tables say for the instant asked: PDT in a Pacific summer, PST in its winter, BST or GMT in London, AEDT or AEST in Melbourne; the page never writes one for the other, and "Pacific time" is expanded to whichever is in force on the date in question.
A clock change makes two kinds of trouble for a converted time, and both are reported rather than moved: an hour the spring-forward removes (2:30 AM on the day the clocks jump from 2:00 to 3:00 does not exist — the page says so and names where the clock landed), and an hour the fall-back repeats (1:30 AM happens twice; the page gives both, the first in daylight time and the second in standard). Dates are explicit in both places, because a converted evening is often tomorrow morning on the other side.
The pair pages find the year's changes in either zone and give the difference after each; the city pages show the day's light beside the clock, because the hour alone says nothing about the sky. The nightly bake fixes the zone facts and the year's dates; the clocks themselves run in your browser.
Make time for the light. Sol for iPhone is coming soon.
Sol for iPhone · Coming soon