What is the shortest month of the year?

February is the shortest month because it has 28 days in common years and 29 days in leap years, while all other months have 30 or 31 days. Leap years add the extra day to keep our calendar aligned with Earth’s orbit around the Sun. Historically, the Roman calendar originally had 10 months; January and February were added later by King Numa Pompilius, with February placed at the end and given fewer days. Julius Caesar’s Julian calendar and later the Gregorian reform set the leap-year system. February’s name comes from “Februa,” a Roman purification festival. Memory tip: use the rhyme “Thirty days hath September…” or the knuckle trick—February is the dip between knuckles.