夏至
夏至为每年6月21日或6月22日,是北半球这一年中白昼最长,太阳角度最高的一天,它标志着夏天的到来。 "不过夏至不热","夏至三庚数头伏"。夏至虽表示炎热的夏天已经到来,但还不是最热的时候,夏至后的一段时间内气温仍继续升高,大约再过二三十天,一般就是最热的天气了。
在此节气之后太阳直射地面的位置逐渐南移,北半球的白昼日渐缩短,而此时南半球正值隆冬。
夏至以后地面受热强烈,空气对流旺盛,午后至傍晚常见雷阵雨。这种热雷雨骤来疾去,降雨范围小,人称"夏雨隔田坎"。唐代诗人刘禹锡曾巧妙地借用这种天气,写出"东边日出西边雨,道是无晴却有晴"的著名诗句。
北京人在夏至这天讲究吃面,按照老北京的风俗习惯,每年一到夏至就可以大吃生菜、凉面了,因为这个时候天气炎热,吃些生冷的食物可以降火开胃,又不至于因为寒凉而损害健康。
与北欧地区的居民把仲夏节当作重要节日不同,中国人不太庆祝夏至,很少有人过仲夏节。
Summer Solstice
Summer Solstice falls on the 21st or 22nd of June each year. It has the longest day time of the year in the Northern Hemisphere, and the sun altitude is also the highest. Summer Solstice indicates the coming of the summer. "It won't get hot before the Summer Solstice". "When summer comes to the third seventh day of the ten Heavenly Stems, it is just the first period of the dog days." Though Summer Solstice shows that summer has come, but it is not the hottest time. After Summer Solstice, the temperature keeps rising for a period and in another twenty or thirty days usually comes the hottest weather.
After this day, the spot of the direct sunlight gradually moves southward. The day time in the Northern Hemisphere is getting shorter, whereas it is already midwinter in the Southern Hemisphere.
After the day of Summer Solstice, the ground is strongly heated, the air convection is vigorous, and thunderstorms often come between afternoon and evening. Weather changes suddenly and the rain falls just within a small range of areas, as people always say "the rain in summer is only separated by baulks". A Tang Dynasty poet Liu Yuxi skillfully borrowed the feature of such weather and wrote the famous lines "With sunshine in the east and rain in the west, you can't tell whether it's fine or not."
The people in Beijing are used to eating noodles on the day of Summer Solstice. According to the old customs in Beijing, when it comes to the day of Summer Solstice, people can safely start eating uncooked vegetables and cold noodles. Because it is hot at this time, eating these kinds of food can help reduce heat and stimulate appetite, and it is the least harmful to the health with this coldness after the day.
Unlike the people in the North Europe who regard the day of midsummer as an important festival, the Chinese seldom celebrate the day of Summer Solstice, let alone the day of midsummer.