立冬在11月7-8日之间，即太阳位于黄经225°。2018年的立冬就在今天。立，建始也，表示冬季自此开始。冬是终了的意思，有农作物收割后要收藏起来的含意，中国又把立冬作为冬季的开始。
The traditional East Asian calendars divide a year into 24 solar terms. Lìdōng (pīnyīn) is the 19th solar term. It begins when the Sun reaches the celestial longitude of 225° and ends when it reaches the longitude of 240°. It more often refers in particular to the day when the Sun is exactly at the celestial longitude of 225°. In the Gregorian calendar, it usually begins around November 7 and ends around November 22. Lidong signifies the beginning of winter in East Asian cultures.
立冬前后，中国大部分地区降水显著减少。中国东北地区大地封冻，农林作物进入越冬期。中国江淮地区的“三秋”已接近尾声，中国江南则需抢种晚茬冬麦，赶紧移栽油菜，中国南部则是种麦的最佳时期。另外，立冬后空气一般渐趋干燥，土壤含水较少，中国此时开始注重林区的防火工作。
二十四节气是中国古代订立的一种用来指导农事的补充历法，是在春秋战国时期形成的。二十四节气能反映季节的变化，指导农事活动，影响着千家万户的衣食住行。那么用英语该如何表达它们呢?
二十四节气 The 24 Solar Terms
立春
start of spring
春天开始之时。
Spring starts here according to the Chinese definition of a season.
雨水
rain water
降雨大于降雪。
Starting at this point, the temperature makes rain more likely than snow
惊蛰
awakening of insects
冬眠昆虫开始苏醒。
When hibernating insects awaken.
春分
spring equinox
平分春季。
The central divide of spring
清明
clear and bright
扫墓时节。
A Chinese festival where, traditionally, ancestral graves are tended.
谷雨
grain rains
雨水帮助谷物生长。
Rain helps grain grow.
立夏
start of summer
夏天开始之时。
Summer starts here.
小满
grain full
谷物变得饱满。
Grains are plump.
芒种
grain in ear
植物的芒生长成熟。
Awns (beard of grain) grow.
夏至
summer solstice
太阳高度达到了极值(最高)。
Summer extreme (of sun's height)
小暑
minor heat
气温开始高到难以忍受。
When heat starts to get unbearable.
大暑
major heat
一年最热之时。
The hottest time of the year.
立秋
start of autumn
秋天开始之时。
Autumn starts here.
处暑
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炎热的夏天即将过去。
The scorching summer is going to pass by.
白露
white dew
凝结的水汽变白。
Condensed moisture makes dew white.
秋分
autumn equinox
平分秋季。
The central divide of autumn.
寒露
cold dew
露水开始变成霜。
Dew starts turning into frost.
霜降
descent of frost
霜开始出现，气温开始下降。
Appearance of frost and descent of temperature.
立冬
start of winter
冬天开始之时。
Winter starts here.
小雪
minor snow
开始下雪。
Snow starts falling.
大雪
major snow
雪开始下大。
Season of snowstorms in full swing.
冬至
winter solstice
太阳高度达到了极值(最低)。
Winter extreme (of sun's height).
小寒
minor cold
气温开始低到难以忍受。
Cold starts to become unbearable.
大寒
major cold
一年最冷之时。
Coldest time of year.