Which months of the year have five weeks?

There are no months that ever have 5 full weeks, or even 5 full work weeks within them. There can be 5 of a given week day within a month. This happens all the time in the months with 30 or with 31 days. They will have 2 or 3 week days that occur 5 times during the month. It never happens in a non-leap year February which has 28 days, exactly 4 weeks. In leap years, February will have 5 of one of the week days, because February will have 29 days in those years. As you know, the length of the year in days is not evenly divisible by 7, so there is an off-set in terms of which days occur 4 or 5 times in a given month. It's different from year to year.