The short answer is that we inherited the calendar from the Romans who originally had calendars of ten months starting in March (spring), the winter days being simply "off calendar." When the winter months were created, there were twelve months: 7 with 29, 1 with 28, and 4 with 31 to make 355 days.
As this threw the calendar off related to the observed seasons, a 13th "leap month" or "intercalary" would be added between February and March which had 27 days, and February was reduced to either 23 or 24. The reforms of 45 BC led to the Julian calendar with the same number of days in each month as currently observed. February inherited the intercalary day (February 29), every 4 years with some exceptions.
Because there are 365.25 days in a year and every 4 years that is a leap year an extra day is added to February.
February has 28 days in the normal days and 29 days in the leap year.
There were 28 days in February of 1999. Only on Leap Years is there an additional day.
The ordinary months of February usually has 28 days while a leap year usually has 29 days.
There are 28 days in February 2011.
February has only 28 days. Every four years, it has twenty nine. This is known as a "leap" year.
There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.There were 28 days in February 1971.
There are 28 days in February.
February 1930, had 28 days.
February has 28 days in the normal days and 29 days in the leap year.
There were 28 days in February of 1999. Only on Leap Years is there an additional day.
The month of February has 28 days except on Leap Year when it has 29 days.
28 days.28 days.
The ordinary months of February usually has 28 days while a leap year usually has 29 days.
There were 28 days in February 1941.
February 2010 has 28 days.
There were 28 days in February 1954.
There were 28 days in February 1885.