The getTimeZoneTransition() method of Temporal.ZonedDateTime instances returns a Temporal.ZonedDateTime object representing the closest instant after or before this instant at which the time zone's UTC offset changes (the returned instant is the first instant after the change), or null if there is no such transition. This is useful for finding out the offset rules of a time zone, such as its daylight saving time pattern.

Note that instants returned about the future may be unreliable, for example due to changes to the time zone definitions.

Syntax

getTimeZoneTransition(direction)
getTimeZoneTransition(options)

Parameters

direction

A string representing the direction option. This is a convenience overload, so getTimeZoneTransition(direction) is equivalent to getTimeZoneTransition({ direction }), where direction is a string.

options

An object containing the following property:

direction

Whether to search before or after the current instant. Must be one of "next" or "previous".

Return value

A Temporal.ZonedDateTime object with instant t, such that:

• The time zone offset at t is different from the offset one nanosecond before t.
• t < this.epochNanoseconds if direction is "previous", or t > this.epochNanoseconds if direction is "next".
• For all instants between this.epochNanoseconds and t, exclusive, the offset is constant.

If there is no such transition, null is returned.

Examples

Finding the next time zone transition

const dt = Temporal.ZonedDateTime.from("2024-01-01T00-05:00[America/New_York]");
const transition = dt.getTimeZoneTransition("next");
console.log(transition.toString()); // "2024-03-10T03:00:00-04:00[America/New_York]"

const transition2 = transition.getTimeZoneTransition("next");
console.log(transition2.toString()); // "2024-11-03T01:00:00-05:00[America/New_York]"

const transition3 = dt.getTimeZoneTransition("previous");
console.log(transition3.toString()); // "2023-11-05T01:00:00-05:00[America/New_York]"

const dt2 = Temporal.ZonedDateTime.from("2024-01-01T00Z[UTC]");
console.log(dt2.getTimeZoneTransition("next")); // null

Specifications

Browser compatibility

See also

• Temporal.ZonedDateTime
• Temporal.ZonedDateTime.prototype.with()
• Temporal.ZonedDateTime.prototype.add()
• Temporal.ZonedDateTime.prototype.subtract()
• Temporal.ZonedDateTime.prototype.timeZoneId
• Temporal.ZonedDateTime.prototype.offset