一年一度的冬至來囉，記得吃湯圓暖暖身喔！Winter solstice is a very important solar term in Chinese Lunar calendar.

冬至是一年廿四個節氣中，最重要的一個節氣。它的由來，和曆法有直接的關聯。冬至的日期，每年都在陽曆的十二月二十二日或二十三日；陰曆的日期則不太一定，但大抵不超過陰曆的十一月。

冬至在《尚書》「堯典」中稱為「日短」，因為這天太陽直射南回歸線，所以北半球白天最短，黑夜最長。過了冬至後，日光照射北移，白天愈來愈長，黑夜愈來愈短。古人說：「冬至一陽生」，指的就是陰氣到冬至時盛極而衰。相反的，陽氣則從此開始萌芽。

除了在氣候上作為寒暑交替的轉捩點外，冬至也因為容易被測定，所以常被用來作為推算曆法中節氣的依據。周代建子，就以冬至所在的十一月為正月。至少到了漢代，冬至就是個公定節日，百官皆可放假一天。《後漢書》「禮儀志」中記載：「冬至前後，加子安身靜體，百官絕事，不聽政，擇吉辰而後省事。」民間也有句話說：「冬至大如年」，冬至之備受重視，由此可見一斑。

一般來說，冬至時北方大多吃水餃或者是餛飩，而湯圓才是南方的必備食品，因為古時侯有「冬餛飩，年發飥」的說法，也有人用餛飩來祭祖，古時的富貴人角講究新奇，在一碗餛飩中作出十幾種口味，稱為「百味餛飩」，而冬至當天為什麼要吃餛飩呢，根據富察敦崇的『燕京歲時記』中記載：「夫餛飩之形有如雞卵，頗似天地渾沌之象，故於冬至日食之」。

   

我們的冬至「湯圓文化」大約由宋朝開始，明清以後，江南人也在冬至以湯圓祭祖、祭灶，其中湯圓有分大小，有餡而大者稱為「粉團」是晚上祭祖的供品；而無餡較小的是「粉圓」，是早上拜神的供品。

Being a traditional holiday as well, it is still now celebrated quite often in many regions. Early during the Spring and Autumn period, 2500 odd years from now, Winter solstice was first determined as the Chinese traditional solar term among the total 24 terms. In Gregorian calendar, it is around Dec 22nd or 23rd.

Midwinter day is the very day in North hemisphere with the shortest day and longest night year-round. After it, daytime will become increasingly longer and the coldest clime will invade all the places on the Northern part of the globe. We Chinese always call it "JinJiu", which means once Winter solstice comes, we will meet the coldest time ahead. 

That conclusion is proved well founded. According to scientific results, on Winter solstice, a right angle is formed by the sun and the tropic of Capricorn. Thus, the North hemisphere receives the least sunlight and the shortest day and longest night occur.

 Ancient china did pay great attention to this holiday, regarding it as a big event. There was the saying that "Winter solstice holiday is greater than the spring festival". Nowadays, many regions still celebrate it as a big holiday. Northerners may have dumplings and raviolis that day while southerners may have dumplings made by rice and long noodles. Some places even have the tradition to offer sacrifices to the heaven and earth.