Our Lunar year has a leap month 7 times in a 19 year cycle so that the months stay aligned to the agricultural seasons in order for our holidays to coincide with the proper season. It's a little complicated but the lunar year is about 10 days short of a solar year, so every 3 years approximately, we have lost a month. We pop a 13th month in to keep things aligned. In 2016, we will have a 13 month year next.
