Guides

In-depth explainers on how time works around the world.

• How Time Zones Work

  Why time zones exist, how UTC offsets work, and why some zones use 30 or 45-minute offsets.

• How to Schedule Meetings Across Time Zones

  Practical guide to scheduling across time zones without the usual mistakes.

• Daylight Saving Time Explained

  Why DST exists, who uses it, and how the clock changes work.

• ISO Week Numbers Explained

  How ISO 8601 week numbers work, and why some years have 53 weeks.

• UTC vs GMT: What’s the Difference?

  UTC and GMT explained: what each means, when they differ, and which to use.

• How Sunrise and Sunset Are Calculated

  The astronomy behind sunrise/sunset times, twilight, and polar day/night.