PHP Manual: Sets the time

Object-oriented style

public DateTime DateTime::setTime(
    int $hour,
    int $minute,
    int $second = 0,
    int $microsecond = 0
)

Procedural style

DateTime date_time_set(
    DateTime $object,
    int $hour,
    int $minute,
    int $second = 0,
    int $microsecond = 0
)

Resets the current time of the DateTime object to a different time.

Like DateTimeImmutable::setTime but works with DateTime.

The procedural version takes the DateTime object as its first argument.

object: Procedural style only: A DateTime object returned by date_create. The function modifies this object.
hour: Hour of the time.
minute: Minute of the time.
second: Second of the time.
microsecond: Microsecond of the time.

Returns the modified DateTime object for method chaining.

Version	Description
8.1.0	The behaviour with double existing hours (during the fall-back DST transition) changed. Previously PHP would pick the second occurrence (after the DST transition), instead of the first occurrence (before DST transition).
7.1.0	The `microsecond` parameter was added.

DateTime::setTime