Which month has 28 days

February is the only month with exactly 28 days in a regular year, making it the shortest month of the calendar by design. This unusual length dates back to Roman calendar reforms, when February was placed at the end of the year and received the leftover days after other months were assigned. When leap years occur every four years, February gains a 29th day to account for Earth's actual orbital period of approximately 365.25 days.

However, if someone asks this as a riddle, the answer changes—technically, all twelve months have at least 28 days, since even the longest months (with 31 days) contain 28 days within them. In practical calendar planning, February's shorter length affects financial calculations, as it reduces the number of business days in the first quarter and influences everything from mortgage interest to subscription billing cycles. Understanding February's unique position helps with accurate scheduling and budgeting throughout the year.