Time zone guides
Practical explanations of UTC and GMT, daylight saving time, scheduling meetings across time zones, and Unix timestamps.
UTC vs GMT: what’s the difference?
How UTC and GMT differ, why London isn’t on GMT all year, and which one to use in a meeting invitation.
Daylight saving time explained
What happens to skipped and repeated hours when clocks change, and how daylight saving time changes the difference between cities.
How to schedule meetings across time zones
How to pick a fair meeting time across time zones, write an invitation everyone reads the same way, and avoid daylight saving mistakes.
What is a Unix timestamp?
What epoch time is, how to tell seconds from milliseconds, and how to convert a Unix timestamp to a date.