Dates and Time Zones

The bug that corrupts data and breaks launches: UTC versus local, offsets versus zones, DST, and the rules that keep time from wrecking your app.

1. A Moment Is Not a Clock Reading The core split: an instant on the timeline versus the local wall-clock string a human reads. UTC, Unix timestamps, and why '3pm' is not a moment until you say where.
2. Offsets, Zones, and the Golden Rules Why +02:00 is not the same as Europe/Berlin, what the IANA database actually is, and the small set of rules that keep your time handling safe.
3. The 2am That Happens Twice Daylight saving creates gaps where time skips and overlaps where it repeats. The off-by-one-hour bug, the ambiguous timestamp, and why naive math breaks.