<P> The Julian calendar has a regular year of 365 days divided into 12 months , as listed in the table below . A leap day is added to February every four years . The Julian year is , therefore , on average 365.25 days long . It was intended to approximate the tropical ( solar ) year . Although Greek astronomers had known , at least since Hipparchus , a century before the Julian reform , that the tropical year was slightly shorter than 365.25 days , the calendar did not compensate for this difference . As a result , the calendar year gains about three days every four centuries compared to observed equinox times and the seasons . This discrepancy was corrected by the Gregorian reform of 1582 . The Gregorian calendar has the same months and month lengths as the Julian calendar , but , in the Gregorian calendar , years evenly divisible by 100 are not leap years , except that years evenly divisible by 400 remain leap years . Consequently -- since 16 February Julian / 1 March 1900 Gregorian and until 15 February Julian / 28 February 2100 Gregorian -- the Julian calendar is currently 13 days behind the Gregorian calendar . </P>
<P> The Julian calendar has a regular year of 365 days divided into 12 months , as listed in the table below . A leap day is added to February every four years . The Julian year is , therefore , on average 365.25 days long . It was intended to approximate the tropical ( solar ) year . Although Greek astronomers had known , at least since Hipparchus , a century before the Julian reform , that the tropical year was slightly shorter than 365.25 days , the calendar did not compensate for this difference . As a result , the calendar year gains about three days every four centuries compared to observed equinox times and the seasons . This discrepancy was corrected by the Gregorian reform of 1582 . The Gregorian calendar has the same months and month lengths as the Julian calendar , but , in the Gregorian calendar , years evenly divisible by 100 are not leap years , except that years evenly divisible by 400 remain leap years . Consequently -- since 16 February Julian / 1 March 1900 Gregorian and until 15 February Julian / 28 February 2100 Gregorian -- the Julian calendar is currently 13 days behind the Gregorian calendar . </P>
how many days in a julian calendar year
how many days in a julian calendar year
365.25
365.25