Reference · Dates

date.date_in

date.date_in(str, str | null=) -> str

What it does

The calendar date of a date-time in a time zone: what day it is there at that instant, as ISO text "YYYY-MM-DD". The zone is an IANA name (see date.valid_zone), "UTC" or an offset like "+05:30" or "+0530"; left out, it is UTC. It is also the way from a date-time to a date for the functions that take only dates (date.add_days, date.days_between and the rest).

Examples

print(date.date_in("2026-10-27T23:30:00Z", "Asia/Tokyo"), date.date_in("2026-10-27T03:30:00Z", "America/Los_Angeles"))print(date.date_in("2026-10-27T23:30:00Z"))print(date.date_in("2026-10-27T15:30:00+01:00") | date.add_days(1))

2026-10-28 2026-10-262026-10-272026-10-28

Edge cases

• Without a zone the date is UTC's, not the one written: "2026-10-27T00:30:00+02:00" is still the 26th in UTC.
• With the date-time's own offset as the zone, it is the date as written.
• Daylight saving is followed on that day in a named zone.

print(date.date_in("2026-10-27T00:30:00+02:00"), date.date_in("2026-10-27T00:30:00+02:00", "+02:00"))print(date.date_in("2026-10-27T23:30:00Z", "+01:00"), date.date_in("2026-07-01T22:30:00Z", "Europe/Paris"))

2026-10-26 2026-10-272026-10-28 2026-07-02

Errors

A date instead of a date-time, text that is neither, or an unknown zone is a runtime error, not an error value.

print(date.date_in("2026-10-27", "UTC"))

line 1: `date.date_in` expects a date-time (like 2026-10-27T14:30:00Z) as argument 1, got "2026-10-27"

print(date.date_in("2026-10-27T14:30:00Z", "Paris"))

line 1: `date.date_in`: unknown time zone "Paris"

Chaining

print("2026-10-27T23:30:00Z" | date.date_in("Asia/Tokyo") | date.weekday)print(date.from_ms(1793111400000) | date.date_in("Pacific/Auckland") | date.format({ locale: "en-NZ", style: "full" }))

3Wednesday, 28 October 2026

See also

date.to_zone, date.at, date.today, date.add_days, date.parts

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