Why does 춘하추동 (春夏秋冬) start with 춘?

When listing the seasons of the year, Koreans often say "춘하추동 (春夏秋冬)," which literally means "spring (春) summer (夏) fall (秋) winter (冬)." The reason they start with "spring" (春) is that "spring" is the first three months in the lunar calendar. Since there are twelve months in a lunar year, the four seasons are three months each. Using a solar calendar, 일월 (一月) would translate as "January," 이월 (二月) as "February," and 삼월 (삼월) as "March," but using a lunar calendar, 일월 (一月) would translate as "the first month of spring," 이월 (二月 as "the second month of spring," and 삼월 (三月) as "the third month of spring." That means that 사월 (四月) would translate as "April" using the solar calendar, but could translate as "the first month of summer" using the lunar calendar, or simply "the fourth month of the lunar calendar." Confusing? Here is another way that can be used to refer to the months of a lunar calendar.

If you want to list a progressive series of three in Chinese, you can use the characters 孟 (맹), 仲 (중), and 季 (계).  The character 孟 (맹) means "first"; 仲 (중), "next" or "second"; and 季 (계), "last," so the lunar months can also be written as follows:

1. 孟春 (맹춘) -- "the first month of spring."
2. 仲春 (중춘) -- "the second month of spring"
3. 季春 (계춘) -- "the last month of spring"
4. 孟夏 (맹하) -- "the first month of summer"
5. 仲夏 (중하) -- "the second month of summer"
6. 季夏 (계하) -- "the last month of summer"
7. 孟秋 (맹추) -- "the first month of fall"
8. 仲秋 (중추) -- "the second month of fall"
9. 季秋 (계추) -- "the third month of fall"
10. 孟冬 (맹동) -- "the first month of winter"
11. 仲冬 (중동) -- "the second month of winter"
12. 季冬 (계동) -- "the last month of winter.