The Gregorian calendar has four months with a length of 30 days and seven months that are 31 days long. February is the only month that is 28 days long in common years and 29 days long in leap years. Some months have 30 days and some have 31 days . How many months have 28 days ? Solution for level Brain Test How many months have 28 days ... Answer: Every month has 28 days at least, just follow the walkthrough =)Brain Test All Answers... How many days are there in each month ? With one exception, months have 30 or 31 days —but February lasts for only 28 days in common years and 29 days in leap years. ©timeanddate.com From 10 to 12 Months Our current Gregorian calendar and its predecessor, the Julian calendar, both have 12 months . However, the month names we use today are derived from the Roman calendar, which initially had only 10 months , with the calendar year starting in March (Martius). Calendar with holidays The Romans ...