February

　　Similar to the release of the "Twilight" series of books and movies it is one the coldest, darkest and most depressing periods of the year in the Northern hemisphere; fortunately, it is the shortest month.

　　Of course, unlike "Twilight", not everything related to February is negative. Chinese New Year often falls in February and we also have Valentine's Day, which is good if you have a girlfriend.

　　But why does February only have 28 or 29 days?

　　The old Roman calendar considered winter a monthless period and only had 10 months. The months of January and February were added around 700 BCE so that the calendar would equal a standard lunar year of 355 days. February became the second month of the year around 450 BCE. Before that it was the last month of the year in the old Roman calendar and they would shorten it to either 23 or 24 days depending of the year. They would sometimes add a 13th month after February to realign the year with the seasons. After some time the 13th month was eliminated and leap years were added every fourth year to give us a 29th of February on leap years.

　　Leap Years are needed to keep our calendar in alignment with the Earth's revolutions around the sun. It takes the Earth approximately 365.242199 days - or 365 days, 5 hours, 48 minutes, and 46 seconds (a tropical year) - to circle once around the Sun.

　　However, the Gregorian calendar has only 365 days in a year, so if we didn't add a day on February 29 nearly every 4 years, we would lose almost six hours off our calendar every year. After only 100 years, our calendar would be off by approximately 24 days and after a few hundred years we would have February in the summer!