TimeZone implementations for rust-chrono from the IANA database
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tz @ 4758e88
.gitmodules update tz database (as a git submodule) Nov 5, 2016


Chrono-TZ 0.5.0

Chrono-TZ is a library that provides implementors of the TimeZone trait for rust-chrono. The impls are generated by a build script using the IANA database and parse-zoneinfo.


Documentation is hosted on docs.rs


Put this in your Cargo.toml:

chrono = "0.4"
chrono-tz = "0.5"

Then you will need to write (in your crate root):

extern crate chrono;
extern crate chrono_tz;


Create a time in one timezone and convert it to UTC

use chrono::{TimeZone, Utc};
use chrono_tz::US::Pacific;

let pacific_time = Pacific.ymd(1990, 5, 6).and_hms(12, 30, 45);
let utc_time = pacific_time.with_timezone(&Utc);
assert_eq!(utc_time, Utc.ymd(1990, 5, 6).and_hms(19, 30, 45));

Create a naive datetime and convert it to a timezone-aware datetime

use chrono::{TimeZone, NaiveDate};
use chrono_tz::Africa::Johannesburg;

let naive_dt = NaiveDate::from_ymd(2038, 1, 19).and_hms(3, 14, 08);
let tz_aware = Johannesburg.from_local_datetime(&naive_dt).unwrap();
assert_eq!(tz_aware.to_string(), "2038-01-19 03:14:08 SAST");

London and New York change their clocks on different days in March so only have a 4-hour difference on certain days.

use chrono::TimeZone;
use chrono_tz::Europe::London;
use chrono_tz::America::New_York;

let london_time = London.ymd(2016, 3, 18).and_hms(3, 0, 0);
let ny_time = london_time.with_timezone(&New_York);
assert_eq!(ny_time, New_York.ymd(2016, 3, 17).and_hms(23, 0, 0));

Adding 24 hours across a daylight savings change causes a change in local time

use chrono::{TimeZone, Duration};
use chrono_tz::Europe::London;

let dt = London.ymd(2016, 10, 29).and_hms(12, 0, 0);
let later = dt + Duration::hours(24);
assert_eq!(later, London.ymd(2016, 10, 30).and_hms(11, 0, 0));

And of course you can always convert a local time to a unix timestamp

use chrono::TimeZone;
use chrono_tz::Asia::Kolkata;

let dt = Kolkata.ymd(2000, 1, 1).and_hms(0, 0, 0);
let timestamp = dt.timestamp();
assert_eq!(timestamp, 946665000);

Pretty-printing a string will use the correct abbreviation for the timezone

use chrono::TimeZone;
use chrono_tz::Europe::London;

let dt = London.ymd(2016, 5, 10).and_hms(12, 0, 0);
assert_eq!(dt.to_string(), "2016-05-10 12:00:00 BST");
assert_eq!(dt.to_rfc3339(), "2016-05-10T12:00:00+01:00");

You can convert a timezone string to a timezone using the FromStr trait

use chrono::TimeZone;
use chrono_tz::Tz;
use chrono_tz::UTC;

let tz: Tz = "Antarctica/South_Pole".parse().unwrap();
let dt = tz.ymd(2016, 10, 22).and_hms(12, 0, 0);
let utc = dt.with_timezone(&UTC);
assert_eq!(utc.to_string(), "2016-10-21 23:00:00 UTC");

Future Improvements

  • Handle leap seconds
  • Handle Julian to Gregorian calendar transitions
  • Load tzdata always from latest version
  • Dynamic tzdata loading