Chunfen

Solar term

Longitude	Term	Calendar
Spring
315°	Lichun	4 – 5 February
330°	Yushui	18–19 February
345°	Jingzhe	5 – 6 March
0°	Chunfen	20–21 March
15°	Qingming	4 – 5 April
30°	Guyu	20–21 April
Summer
45°	Lixia	5 – 6 May
60°	Xiaoman	21–22 May
75°	Mangzhong	5 – 6 June
90°	Xiazhi	21–22 June
105°	Xiaoshu	7 – 8 July
120°	Dashu	22–23 July
Autumn
135°	Liqiu	7 – 8 August
150°	Chushu	23–24 August
165°	Bailu	7 – 8 September
180°	Qiufen	23–24 September
195°	Hanlu	8 – 9 October
210°	Shuangjiang	23–24 October
Winter
225°	Lidong	7 – 8 November
240°	Xiaoxue	22–23 November
255°	Daxue	7 – 8 December
270°	Dongzhi	21–22 December
285°	Xiaohan	5 – 6 January
300°	Dahan	20–21 January

The traditional East Asian calendars divide a year into 24 solar terms (節氣). Chūnfēn (pīnyīn), Shunbun (rōmaji), or Chunbun/Ch'unbun (romaja) (Chinese and Japanese: 春分; Korean: 춘분; Vietnamese: Xuân phân; literally: "vernal equinox") is the 4th solar term. It begins when the Sun reaches the celestial longitude of 0° and ends when it reaches the longitude of 15°. It more often refers in particular to the day when the Sun is exactly at the celestial longitude of 0°. In the Gregorian calendar, it usually begins around 20 March and ends around 4 April (5 April East Asia time).

Pentads

Date and Time (UTC)

year	begin	end
辛巳	2001-03-20 13:30	2001-04-04 17:24
壬午	2002-03-20 19:16	2002-04-04 23:18
癸未	2003-03-21 00:59	2003-04-05 04:52
甲申	2004-03-20 06:48	2004-04-04 10:43
乙酉	2005-03-20 12:33	2005-04-04 16:34
丙戌	2006-03-20 18:25	2006-04-04 22:15
丁亥	2007-03-21 00:07	2007-04-05 04:04
戊子	2008-03-20 05:48	2008-04-04 09:45
己丑	2009-03-20 11:43	2009-04-04 15:33
庚寅	2010-03-20 17:32	2010-04-04 21:30
辛卯	2011-03-20 23:20	2011-04-05 03:11
壬辰	2012-03-20 05:14	2012-04-04 09:05
癸巳	2013-03-20 11:01	2013-04-04 15:02
甲午	2014-03-20 16:57	2014-04-04 20:46

Source: JPL Horizons On-Line Ephemeris System

Each solar term can be divided into 3 pentads (候). They are: first pentad (初候), second pentad (次候) and last pentad (末候). Pentads in Chunfen include:

China

• First pentad: 玄鳥至, 'The dark birds arrive'. 'Dark bird' in this case refers to swallows, which are also making their northward migration.^[1]
• Second pentad: 雷乃發聲, 'Thunder sounds', referring to the onset of spring thunderstorms.^[1]
• Last pentad: 始電, 'Lightning begins'. This refers to thunderstorms as well, but also to the gradual lengthening of daytime, and the prevalence of sunlight.^[1]

Japan

A pentad as follows was referred to Japanese traditional calendar presented in a smaller, easy to use, format.

• First pentad: Suzume hajimete sukuu (雀始巣), 'Sparrow begins holding a nest'.^[2]
• Second pentad: Sakura hajimete hiraku (桜始開), 'Cherry blossoms open for the first time'.^[2]
• Last pentad: Kaminari sunawachi koeo hassu (雷乃発声), 'Distant thunder start to sound'.^[2]

References

1. Kondō Heijō (近藤瓶城), ed. (1901). 新加纂録類 (Shinka Sanrokurui). 改定史籍集覧 (Kaitei Shiseki Shūran) 19. (Meiji 34) (Tokyo: 近藤活版所 (Kondō Kappansho)). p. 110.
2. Fujisawa, Morihiko (1961). 年中行事編 (Nenjū Gyōjihen). 図説日本民俗学全集 (Zusetsu Nihon Minzokugaku Zenshū) 7 (Tokyo: Akane Shobō). p. 103.