Grammar Tips. Comma 4.

When a date consists of the day of the month followed by the year, the day of the month should be followed by a comma.

When the day of the week is provided before the month, the day of the week should be followed by a comma.

INCORRECT: I will be out of town on Wednesday October 31 2018.

CORRECT: I will be out of town on Wednesday, October 31, 2018.