JS Temporal ZonedDateTime
Handle Time Zones Correctly
What You Will Learn:
- How to use JavaScript Temporal.ZonedDateTime
- How to handle time zones correctly
- How to add and subtract date
- How to avoid DST (Daylight Saving Time) bugs
- How to convert between time zones safely
Note
A Temporal.ZonedDateTime represents a date and time with a time zone.
It is the safest way to handle international date and time calculations.
Why ZonedDateTime Is Important
Time zones and daylight saving time (DST) can cause serious bugs when using Date.
ZonedDateTime solves this by always storing the time zone together with the date and time.
Create a ZonedDateTime
You can create a ZonedDateTime from a string that includes a time zone.
Example
const zdt = Temporal.ZonedDateTime.from("2026-02-17T14:30:00+01:00[Europe/Oslo]");
The time zone name is written inside square brackets.
Get Current Date and Time with Time Zone
Use Temporal.Now.zonedDateTimeISO() to get the current date and time with your system's time zone.
Example
const now = Temporal.Now.zonedDateTimeISO();
Convert Between Time Zones
You can convert a ZonedDateTime to another time zone.
Example
const oslo = Temporal.ZonedDateTime.from("2026-02-17T14:30:00+01:00[Europe/Oslo]");
const newYork = oslo.withTimeZone("America/New_York");
The exact moment stays the same, but the local clock time changes.
Add Time Safely (DST Safe)
Adding days across a daylight saving change can break with Date.
ZonedDateTime handles this correctly.
Example
const start = Temporal.ZonedDateTime.from("2026-03-29T00:00:00+01:00[Europe/Oslo]");
const nextDay = start.add({ days: 1 });
Temporal adjusts automatically if a DST change happens.
Convert from Instant
An Instant represents a UTC moment.
You can convert it to a ZonedDateTime in a specific time zone.
Example
const instant = Temporal.Now.instant();
const zoned = instant.toZonedDateTimeISO("Europe/Oslo");
When to Use ZonedDateTime
International applications.
Booking systems.
Flight or travel systems.
Applications that must handle DST correctly.
Any system where time zones matter.
ZonedDateTime vs PlainDateTime
| Type | Includes Time Zone | Use Case |
|---|---|---|
PlainDateTime |
No | Local scheduling without conversion |
ZonedDateTime |
Yes | International or DST-aware systems |
Summary
Temporal.ZonedDateTime is the safest way to handle date and time with time zones.
It prevents common DST bugs and makes time zone conversions clear and predictable.
