Guides

The why behind the clock and the sky

Our tools give you the numbers. These plain-English guides explain where the numbers come from — no jargon, no fluff.

🌍 How time zones work

UTC, offsets, half-hour zones, and the volunteer-run database that keeps every phone on Earth honest. Why railroads invented the whole system, and why China runs on a single clock.

🕐 Daylight saving time, explained

Why we spring forward and fall back, which countries refuse to, what the switch does to your body, and practical tips for surviving it twice a year.

🌙 Moon phases without the jargon

Why the Moon changes shape, the one-second trick to tell waxing from waning, what supermoons and blue moons really are, and the best nights for stargazing.

⛅ How weather forecasts are made

Balloons, satellites, supercomputers, and the butterfly effect — plus what "70% chance of rain" actually means and how far ahead you can trust a forecast.

Why we write these

Time & Sky started as a set of fast, free tools — a world clock, a time zone converter, a weather forecast, and friends. But the questions behind the tools are genuinely interesting: why the world argues about clock time, why the Moon waxes and wanes, why a forecast is trustworthy on Tuesday and shaky by Sunday. These guides are our answers, written to be read by anyone. More are on the way.