`isdst`

Tests whether datetime values fall in daylight saving time.

Category: Language Fundamentals > Data Types

Syntax

tf = isdst(t)

Returns a logical array telling which elements of the datetime array t are in daylight saving time.

Description

A datetime with a time zone carries the rules of that zone, including the dates when clocks move forward and back. isdst consults those rules for each element.

A datetime with no time zone has no rules to apply, so the result is false everywhere.

Input arguments

t: datetime array. It needs a time zone to give a meaningful answer.

Output arguments

tf: Logical array the same size as t; true where daylight saving time is in effect.

Example

Winter and summer in New York

w = datetime(2024,1,15,'TimeZone','America/New_York');
s = datetime(2024,7,15,'TimeZone','America/New_York');
isdst(w)
isdst(s)

Output

ans = logical
   0
ans = logical
   1

isdst