5 months of dating
One of Wikipedia's sister projects, Wiktionary, provides translations of each of the Gregorian/Julian calendar months into a dozen or more languages.
Month-by-month links are provided here: January, February, March, April, May, June, July, August, September, October, November, December.
The famous mnemonic Thirty days hath September is a common way of teaching the lengths of the months in the English-speaking world.
Also, note that any five consecutive months (not including February) contain 153 days.
However, the motion of the Moon in its orbit is very complicated and its period is not constant.A month is a unit of time, used with calendars, which is approximately as long as a natural period related to the motion of the Moon; month and Moon are cognates.The traditional concept arose with the cycle of Moon phases; such months (lunations) are synodic months and last approximately 29.53 days.This system has been used for hundreds of years and throughout many generations.This calendar is cyclical and relies on the position and shape of the moon.
While some like the Jewish Karaites still rely on actual moon observations, most people use the Gregorian solar calendar.