class

Time::Location

Inherits Reference / Object

Location maps time instants to the zone in use at that time. It typically represents the collection of time offsets observed in a certain geographical area.

It contains a list of zone offsets and rules for transitioning between them.

If a location has only one offset (such as UTC) it is considered fixed.

A Location instance is usually retrieved by name using Time::Location.load. It loads the zone offsets and transitioning rules from the time zone database provided by the operating system.

location = Time::Location.load("Europe/Berlin")
location # => #<Time::Location Europe/Berlin>
time = Time.local(2016, 2, 15, 21, 1, 10, location: location)
time # => 2016-02-15 21:01:10+01:00[Europe/Berlin]

A custom time zone database can be configured through the environment variable TZDIR. See .load for details.

Fixed Offset

A fixed offset location is created using Time::Location.fixed:

location = Time::Location.fixed(3600)
location       # => #<Time::Location +01:00>
location.zones # => [#<Time::Location::Zone +01:00 (0s) STD>]

Local Time Zone

The local time zone can be accessed as Time::Location.local.

It is initially configured according to system environment settings, but its value can be changed:

location = Time::Location.local
Time::Location.local = Time::Location.load("America/New_York")

Constants

UTC = new("UTC", [Zone::UTC])

Describes the Coordinated Universal Time (UTC).

The only time zone offset in this location is Zone::UTC.

Constructors

fixed(name : String, offset : Int32) : Location

Creates a Location instance named name with fixed offset in seconds from UTC.

Source
fixed(offset : Int32) : self

Creates a Location instance with fixed offset in seconds from UTC.

The formatted offset is used as name.

Source
load(name : String) : Location

Loads the Location with the given name.

location = Time::Location.load("Europe/Berlin")

name is understood to be a location name in the IANA Time Zone database, such as "America/New_York". As special cases, "UTC", "Etc/UTC" and empty string ("") return Location::UTC, and "Local" returns Location.local.

The implementation uses a list of system-specific paths to look for a time zone database. The first time zone database entry matching the given name that is successfully loaded and parsed is returned. Typical paths on Unix-based operating systems are /usr/share/zoneinfo/, /usr/share/lib/zoneinfo/, or /usr/lib/locale/TZ/.

A time zone database may not be present on all systems, especially non-Unix systems. In this case, you may need to distribute a copy of the database with an application that depends on time zone data being available.

A custom lookup path can be set as environment variable TZDIR(ZONEINFO is also supported as legacy option). The path can point to the root of a directory structure or an uncompressed ZIP file, each representing the time zone database using files and folders of the expected names.

Example:

Time::Location.load("Custom/Location")

If the TZDIR environment variable is "/usr/share/zoneinfo" this tries to load the file /usr/share/zoneinfo/Custom/Location.

If the TZDIR environment variable is "/path/to/zoneinfo.zip" this tries to load the file Custom/Location in the uncompressed ZIP file at /path/to/zoneinfo.zip.

If the location name cannot be found, InvalidLocationNameError is raised. If the loader encounters a format error in the time zone database, InvalidTZDataError is raised.

Files are cached based on the modification time, so subsequent request for the same location name will most likely return the same instance of Location, unless the time zone database has been updated in between.

  • .load? returns nil if the location is unavailable.
Source
load_local

Loads the local time zone according to the current application environment.

The environment variable ENV["TZ"] is consulted for finding the time zone to use.

  • "UTC", "Etc/UTC" and empty string ("") return Location::UTC.
  • POSIX TZ strings (such as "EST5EDT,M3.2.0,M11.1.0") are parsed using Location.posix_tz.
  • Values beginning with a colon are implementation-defined according to POSIX, and not supported in Crystal.
  • Any other value (such as "Europe/Berlin") is tried to be resolved using Location.load.
  • If ENV["TZ"] is not set, the system's local time zone data will be used (/etc/localtime on unix-based systems).
  • If no time zone data could be found (i.e. the previous methods failed), Location::UTC is returned.
Source
local

Returns the Location representing the application's local time zone.

Time uses this property as default value for most method arguments expecting a Location.

The initial value depends on the current application environment, see .load_local for details.

The value can be changed to overwrite the system default:

Time.local.location # => #<Time::Location America/New_York>
Time::Location.local = Time::Location.load("Europe/Berlin")
Time.local.location # => #<Time::Location Europe/Berlin>
Source
new(ctx : YAML::ParseContext, node : YAML::Nodes::Node)
Source
new(pull : JSON::PullParser)
Source

Class methods

from_json_object_key?(key : String) : Time::Location
Source
load?(name : String) : Location | Nil

Loads the Location with the given name.

location = Time::Location.load("Europe/Berlin")

name is understood to be a location name in the IANA Time Zone database, such as "America/New_York". As special cases, "UTC", "Etc/UTC" and empty string ("") return Location::UTC, and "Local" returns Location.local.

The implementation uses a list of system-specific paths to look for a time zone database. The first time zone database entry matching the given name that is successfully loaded and parsed is returned. Typical paths on Unix-based operating systems are /usr/share/zoneinfo/, /usr/share/lib/zoneinfo/, or /usr/lib/locale/TZ/.

A time zone database may not be present on all systems, especially non-Unix systems. In this case, you may need to distribute a copy of the database with an application that depends on time zone data being available.

A custom lookup path can be set as environment variable TZDIR(ZONEINFO is also supported as legacy option). The path can point to the root of a directory structure or an uncompressed ZIP file, each representing the time zone database using files and folders of the expected names.

Example:

Time::Location.load("Custom/Location")

If the TZDIR environment variable is "/usr/share/zoneinfo" this tries to load the file /usr/share/zoneinfo/Custom/Location.

If the TZDIR environment variable is "/path/to/zoneinfo.zip" this tries to load the file Custom/Location in the uncompressed ZIP file at /path/to/zoneinfo.zip.

If the location name cannot be found, InvalidLocationNameError is raised. If the loader encounters a format error in the time zone database, InvalidTZDataError is raised.

Files are cached based on the modification time, so subsequent request for the same location name will most likely return the same instance of Location, unless the time zone database has been updated in between.

  • .load? returns nil if the location is unavailable.

Returns nil if the location is unavailable. Raises InvalidLocationNameError if the name is invalid. Raises InvalidTZDataError if the loader encounters a format error in the time zone database.

  • .load raises if the location is unavailable.
Source
local=(local : Location)

Returns the Location representing the application's local time zone.

Time uses this property as default value for most method arguments expecting a Location.

The initial value depends on the current application environment, see .load_local for details.

The value can be changed to overwrite the system default:

Time.local.location # => #<Time::Location America/New_York>
Time::Location.local = Time::Location.load("Europe/Berlin")
Time.local.location # => #<Time::Location Europe/Berlin>
Source
posix_tz(name : String, str : String) : TZLocation

Creates a Location instance named name with the given POSIX TZ string str, as defined in POSIX.1-2024 Section 8.3.

str must begin with a standard time designator followed by a time offset; implementation-defined TZ strings beginning with a colon, as well as names from the time zone database, are not supported.

If str designates a daylight saving time, then the transition times must also be present. A TZ string like "PST8PDT" alone is considered invalid, since no default transition rules are assumed.

location = Time::Location.posix_tz("America/New_York", "EST5EDT,M3.2.0,M11.1.0")
Time.utc(2025, 3, 9, 6).in(location)  # => 2025-03-09 01:00:00.0 -05:00 America/New_York
Time.utc(2025, 3, 9, 7).in(location)  # => 2025-03-09 03:00:00.0 -04:00 America/New_York
Time.utc(2025, 11, 2, 5).in(location) # => 2025-11-02 01:00:00.0 -04:00 America/New_York
Time.utc(2025, 11, 2, 6).in(location) # => 2025-11-02 01:00:00.0 -05:00 America/New_York
Source

Instance methods

==(other : self)

Returns true if other is equal to self.

Two Location instances are considered equal if they have the same name, offset zones and transition rules.

fixed?

Returns true if this location has a fixed offset.

Locations returned by Location.posix_tz have a fixed offset if the TZ string specifies either no daylight saving time at all, or an all-year daylight saving time (e.g. "EST5EDT,0/0,J365/25").

Source
hash(hasher)

Returns true if other is equal to self.

Two Location instances are considered equal if they have the same name, offset zones and transition rules.

inspect(io : IO) : Nil

Appends a String representation of this object which includes its class name, its object address and the values of all instance variables.

class Person
  def initialize(@name : String, @age : Int32)
  end
end

Person.new("John", 32).inspect # => #<Person:0x10fd31f20 @name="John", @age=32>
Source
local?

Returns true if this location equals to Time::Location.local.

Source
lookup(time : Time) : Zone

Returns the time zone offset observed at time.

Source
lookup(unix_seconds : Int) : Zone

Returns the time zone offset observed at unix_seconds.

unix_seconds expresses the number of seconds since UNIX epoch (1970-01-01 00:00:00Z).

Source
name

Returns the name of this location.

It usually consists of a continent and city name separated by a slash, for example Europe/Berlin.

Source
to_json(json : JSON::Builder) : Nil
Source
to_s(io : IO) : Nil

Prints name to io.

Source
to_yaml(yaml : YAML::Nodes::Builder) : Nil
Source
utc?

Returns true if this location equals to UTC.

Source
zones

Returns the array of time zone offsets (Zone) used in this time zone.

Source

Nested types