There are no calendar months with five full weeks, yet any month with more than 28 days has four full weeks and a portion of the fifth. This is why many months contain five of a particular day of the week.
Although there are no calendar months with five weeks, it is useful to know which months have five Fridays, Saturdays, or Sundays. To determine this, a person must know the number of days in the month and the first day of the week. The first two days of each 30-day month (April, June, September, and November) will occur five times. In January, March, May, July, August, October, and December, the first three weekdays occur five times. With only 28 days, February typically has four of each day. However, the first weekday of February will occur five times during leap years.
