In both the Gregorian and Julian calendars, all months contain 28 or more days. February is the only month that has a total of 28 days (except for leap years when February has 29 days). Because the Romans considered even numbers bad, each month featured an odd number of days that alternated between 29 and 31. However, one month has to be an even number in order to achieve 355 days. With 28 days, February was picked as the unfortunate month. https://mycalcu.com/
The Gregorian calendar features four months of 30 days each and seven months of 31 days each. February is the only month that lasts 28 days in regular years and 29 days in leap years.
The Twelve Months of the Year
Both the Gregorian and Julian calendars have the following twelve months: