二月份 has 28 days

圖片參考：http://en.wikipedia.org/skins-1.5/common/images/magnify-clip.png

February, from the Très riches heures du duc de Berry

Why does February have only 28 days?
January and February both date from shortly after the time of Rome's founding. They were added to a calendar that had been divided into ten month-like periods whose lengths varied from 20 to 35 or more days. Those lengths are believed to have been intended to reflect growth stages of crops and cattle. The winter season was not included.
When introduced, January was given 29 days and put at the beginning of the calendar year. February was given 23 days and put at the end. Then, for an undetermined period shortly after Rome's founding, months were said to have begun when a new moon was first sighted. At some later time, month lengths were separated from lunations and again became fixed. At that time, February's original length was extended by five days to give it a total of 28. If you would like to read about other nations that also added five days to their calendars close to the same time see my 8th to 4th Century B.C. Calendar Changes.

http://www.12x30.net/faq.html#February




Historical names for February include the Anglo-Saxon terms Solmoneth (mud month) and Kale-monath (named for cabbage) as well as Charlemagne's designation Hornung. In Finnish, the month is called helmikuu, meaning "month of the pearl".

二月為什麼通常只有二十八天？
這是一個很可笑的典故：話說西元四
十六年羅馬皇帝儒略凱撒(Julius Ca
esar) 修改曆法時，本來規定每年十
二個月裡，逢單是大月三十一日，逢
雙是小月三十日，但是這樣算下來，
一年就變成三百六十六日，所以必須
設法在一年中扣去一天。那時候判處
死刑的人犯均在二月分執行，因此人
們認為二月是不吉利的月分，既然要
扣除一天，那麼就由二月分來扣掉，
讓不吉利的日子減少一天，因此二月
分就成了二十九日。

後來奧古斯都(Augustus)繼凱撒之後
當了羅馬皇帝，他發現凱撒是七月生
的，而七月是逢單為大月三十一日；
他不服氣，為了表示自己也偉大，就
把自己八月出生的月分改為大月三十
一日。糟了又多出一天怎麼辦？嘿！
那還是由二月分來扣除，因此結果二
月分就變成二十八日。