Chunfen
 |
 |
| Term | Longitude | Dates |
|---|---|---|
| Lichun | 315° | 4–5 February |
| Yushui | 330° | 18–19 February |
| Jingzhe | 345° | 5–6 March |
| Chunfen | 0° | 20–21 March |
| Qingming | 15° | 4–5 April |
| Guyu | 30° | 20–21 April |
| Lixia | 45° | 5–6 May |
| Xiaoman | 60° | 21–22 May |
| Mangzhong | 75° | 5–6 June |
| Xiazhi | 90° | 21–22 June |
| Xiaoshu | 105° | 7–8 July |
| Dashu | 120° | 22–23 July |
| Liqiu | 135° | 7–8 August |
| Chushu | 150° | 23–24 August |
| Bailu | 165° | 7–8 September |
| Qiufen | 180° | 23–24 September |
| Hanlu | 195° | 8–9 October |
| Shuangjiang | 210° | 23–24 October |
| Lidong | 225° | 7–8 November |
| Xiaoxue | 240° | 22–23 November |
| Daxue | 255° | 7–8 December |
| Dongzhi | 270° | 21–22 December |
| Xiaohan | 285° | 5–6 January |
| Dahan | 300° | 20–21 January |
The traditional East Asian calendars divide a year into 24 solar terms (節氣). Chūnfēn (pīnyīn) or Shunbun (rōmaji) (Chinese and Japanese: 春分; Korean: 춘분; Vietnamese: Xuân phân; "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
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.
- Second pentad: 雷乃發聲, 'Thunder sounds', referring to the onset of spring thunderstorms.
- 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.
- Japan
- First pentad: 雀始巣
- Second pentad: 桜始開
- Last pentad: 雷乃発声