.setUTCMonth()

The .setUTCMonth() method sets the month of a Date object according to universal time (UTC).

Syntax

dateObject.setUTCMonth(month)
dateObject.setUTCMonth(month, day)

The .setUTCMonth() method is called on dateObject with the integer input argument month, and optionally day.

• month (required): Expected values are in the range between 0-11, but other values are accepted:

  • -1 will set dateObject to the last month of the previous year
  • 12 will set dateObject to the first month of the following year

• day (optional): Expected values are in the range between 1-31, but other values are accepted:

  • Any value smaller than 1 will roll over to the previous month (0 will set dateObject to the last day of the previous month)
  • Any value greater than the number of days in a month will roll over to the following month

Examples

This example sets the month and day and returns a variety of date formats to the console.

const dateObject = new Date('2020-05-10T00:00:00');
dateObject.setUTCMonth(2, 20); // Month, Day (optional)

console.log(dateObject);
console.log(dateObject.toUTCString());
console.log(
  'Month: ' + dateObject.getUTCMonth(),
  '\nDay: ' + dateObject.getUTCDay()
);

The code above results in the following output:

2020-03-20T00:00:00.000Z
Fri, 20 Mar 2020 00:00:00 GMT
Month: 2
Day: 5

Note: The first month of the year is 0, the first day of the month is 1.

This example showcases the rollover of dates with values outside of the expected range:

const dateObject = new Date(Date.UTC(2000, 1, 2, 3, 4, 5)); // Year, Month, Day, Hour, Minute, Second, Millisecond

dateObject.setUTCMonth(0, 1); // 1st month of year, 1st day of month
console.log(dateObject, '=', dateObject.toUTCString());

dateObject.setUTCMonth(-1); // Month out of range, rolls over to previous year
console.log(dateObject, '=', dateObject.toUTCString());

dateObject.setUTCMonth(12, 32); // Month and day out of range, rolls over to following year and month
console.log(dateObject, '=', dateObject.toUTCString());

The code above results in the following output:

2000-01-01T03:04:05.000Z = Sat, 01 Jan 2000 03:04:05 GMT
1999-12-01T03:04:05.000Z = Wed, 01 Dec 1999 03:04:05 GMT
2000-02-01T03:04:05.000Z = Tue, 01 Feb 2000 03:04:05 GMT