Every time zone problem traces back to one reference point: UTC. Local times, abbreviations like EST or CET, and the twice-yearly shift of daylight saving time are all just offsets applied to that one fixed baseline. Once UTC clicks, the rest of time zone arithmetic is addition and subtraction — the hard part is knowing which offset applies where and when.
This category is for anyone who needs to work across zones: reading a UTC timestamp, decoding an unfamiliar abbreviation on a flight board, figuring out whether a country observes daylight saving, or lining up a meeting for people in three different cities. You'll find what UTC is, how it differs from GMT, a reference for common abbreviations, how DST changes the offset, and the methods for converting times and scheduling across zones without losing track of a day.
Start with the UTC guide if the concept is new. If you already have the baseline down, jump straight to conversion, scheduling, or the abbreviation reference.
Start here
New to the topic? Read What Is UTC? Coordinated Universal Time, Explained Simply first — it's the cornerstone of this category and gives you the reference point everything else builds on.
All guides in this category
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Category FAQ
Which post should I read first?
Start with What Is UTC? It's the cornerstone of this category and gives you the reference point every other post builds on.
What does the Time Zones category cover?
What UTC and GMT are and how they differ, how to read common time zone abbreviations, how daylight saving time works, and how to convert times and schedule meetings across zones.
Do I need to read these in order?
No. Each post answers its own question and stands alone. Read the one that matches what you need right now; the guides link out to each other where it's relevant.