Why are months different lengths?

Question

Why do months of the year have different numbers of days? Who established the calendar and what is the logic behind it?
Ross, Basildon

Answer

** Definitive **
Name: John, Caterham
Qualification: I'm a calendar expert
Answer: The calendar was invented by the Romans and there were 10 months in the year - Sept, Oct, Nov and Dec should be the 7th-10th months of the year. But Julius Caesar was rather arrogant and wanted a calendar across the whole empire, so he got a Greek to make a calendar that contained two extra months which were named after him - Julius and Augustus (July and August). One other interesting fact: up until the 1700s when the Augustinian calendar came into operation, the first day of the year was March 25th. Pope Augustin moved the date 11 days forward to April 5th - which is still used as the first day of the financial year.

** Definitive **
Name: Alan, Kensington
Qualification: Even more of an expert!
Answer: The man before had sort of the right answer, but it needs expanding. Julius Caesar revamped the calendar with the help of an Egyptian astrologer and he decided to change the sixth month to his name. It was some time later that the Emporor Augustus added the month August. The reason that some months are longer than others is that to make their months longer, they took months from other days. So July and August are both 31 days, while others are shorter.