ThesetHours() method ofDate instances changes the hours, minutes, seconds, and/or milliseconds for this date according to local time.

Try it

const event = new Date("August 19, 1975 23:15:30");event.setHours(20);console.log(event);// Expected output: "Tue Aug 19 1975 20:15:30 GMT+0200 (CEST)"// Note: your timezone may varyevent.setHours(20, 21, 22);console.log(event);// Expected output: "Tue Aug 19 1975 20:21:22 GMT+0200 (CEST)"

Syntax

setHours(hoursValue)setHours(hoursValue, minutesValue)setHours(hoursValue, minutesValue, secondsValue)setHours(hoursValue, minutesValue, secondsValue, msValue)

Parameters

hoursValue

An integer between 0 and 23 representing the hours.

minutesValueOptional

An integer between 0 and 59 representing the minutes.

secondsValueOptional

An integer between 0 and 59 representing the seconds. If you specifysecondsValue, you must also specifyminutesValue.

msValueOptional

An integer between 0 and 999 representing the milliseconds. If you specifymsValue, you must also specifyminutesValue andsecondsValue.

Return value

Changes theDate object in place, and returns its newtimestamp. If a parameter isNaN (or other values that getcoerced toNaN, such asundefined), the date is set toInvalid Date andNaN is returned.

Description

If you do not specify theminutesValue,secondsValue, andmsValue parameters, the same values as what are returned bygetMinutes(),getSeconds(), andgetMilliseconds() are used.

If a parameter you specify is outside of the expected range, other parameters and the date information in theDate object are updated accordingly. For example, if you specify 100 forsecondsValue, the minutes are incremented by 1 (minutesValue + 1), and 40 is used for seconds.

BecausesetHours() operates on the local time, crossing a Daylight Saving Time (DST) boundary may result in a different elapsed time than expected. For example, if setting the hours crosses a spring-forward transition (losing an hour), the difference in timestamps between the new and old date is one hour less than the nominal hour difference. Conversely, crossing a fall-back transition (gaining an hour) result in an extra hour. If you need to adjust the date by a fixed amount of time, consider usingsetUTCHours() orsetTime().

If the new local time falls within an offset transition, the exact time is derived using the same behavior asTemporal'sdisambiguation: "compatible" option. That is, if the local time corresponds to two instants, the earlier one is chosen; if the local time does not exist (there is a gap), we go forward by the gap duration.

Examples

Using setHours()

const theBigDay = new Date();theBigDay.setHours(7);

Specifications

Browser compatibility

See also

• Date.prototype.getHours()
• Date.prototype.setUTCHours()