Date and time

Rust has three main date and time crates. chrono is the longest-established and is used across the ecosystem, including as an optional feature in sqlx, serde-based APIs and many web frameworks. It handles dates, times, durations and formatting, with time zones through the companion chrono-tz crate.

jiff, by the author of ripgrep and regex, is newer and is inspired by JavaScript's Temporal proposal. It treats time zones as a first-class part of its zoned datetime type, uses the system tz database or a bundled copy, and handles daylight-saving transitions and calendar arithmetic carefully, which makes mistakes like adding a day across a DST change less likely. The time crate is a smaller, focused alternative with good formatting and parsing.

For new code that deals with real-world time zones, jiff is worth evaluating first, while chrono is the safest choice for compatibility with other crates. Smaller entries cover narrow jobs: ms parses strings like 2h into milliseconds, and nt-time and dos-date-time convert Windows and DOS timestamp formats.