How many days are in each month?
Quick Answer: There are 31 days in January, March, May, July, August, October, and December; 30 days in April, June, September, and November; and 28 days in February, except 29 days in leap years.
Months vary in length because of how our calendar evolved to align roughly with the Earth's orbit around the Sun. Most months have either 30 or 31 days, while February is shorter to fit the calendar year.
Every four years, we add an extra day to February, making it 29 days long. This leap year adjustment keeps our calendar in sync with the solar year.