February is the shortest month, with 28 days in common years and 29 in leap years.

The longer version

Early Roman calendars treated the dead of winter as an afterthought, and the year effectively ran out of days before reaching it. February ended up last and shortest, and later adjustments trimmed it further so that other months could be lengthened. The result is a month of 28 days while its neighbours keep 30 or 31.

That odd length creates practical annoyances. Rent, salaries and interest all have to be divided by a smaller base, and people born on the 29th celebrate a genuine matching date only occasionally. Analysts who compare month-to-month figures usually rescale February, because raw counts make it look as though activity collapsed.

Where this entry sits

These facts wander through clocks, calendars, time zones, and the long human effort to measure passing hours. You will find leap years, odd month lengths, ancient sundials, and the reasons modern timekeeping works the way it does. The full list sits on the Time and Calendars page, where every entry is listed in order.