1. Climate & Natural Phenomena
Dashu (Major Heat) is the 12th solar term in the traditional Chinese lunar calendar, usually beginning around July 22 and ending on August 7. During this period, the sun reaches the 120° celestial longitude. Most parts of China experience their highest temperatures of the year, often accompanied by heavy humidity and thunderstorms.
Ancient Chinese phenology divided Major Heat into three distinctive micro-seasons (Penthads / 三候):
腐草为萤 Fireflies emerge from decaying weeds and reeds as the humidity reaches its summer peak.
土润溽暑 The soil becomes intensely humid and damp, trapping heat across the plains.
大雨时行 Heavy summer cloudbursts descend, breaking the intense heatwave and preparing the earth for autumn.
2. Lifestyle, Diet & Customs
To counter the intense summer heat and dampness, regional Chinese cultures have developed unique culinary customs and cultural activities over hundreds of years.
🍵 Diet & Health
Traditional Chinese Medicine (TCM) emphasizes “clearing damp heat” and supplementing fluids during Major Heat. Light, water-rich foods take center stage across households:
- Watermelon & Mung Bean Soup: The most popular cooling staples. Mung bean soup is naturally sweet and helps cleanse metabolic heat from the body.
- Herbal “Fu Tea” (伏茶): Brewed with honeysuckle, licorice, and mint, this tea is traditionally placed at crossroads for travelers to drink for free.
- Pineapple and Herbal Chicken: In southern provinces, locals eat specific warming or cooling broths to balance internal humidity.
🏮 Folk Traditions
In coastal Zhejiang province, fishermen have practiced this ritual for hundreds of years. A newly built wooden ship filled with sacrificial foods is pulled out to sea and set alight. It represents casting away illness, summer pestilence, and praying for maritime safety.
📜 Classic Poetry
Dashu has inspired numerous poets throughout Chinese history due to its dramatic weather shifts. Here is a classic piece by Bai Juyi from the Tang Dynasty:
《消暑》 — 白居易 (Tang Dynasty)
何以消烦暑，端坐一院中。
眼前无长物，窗下有清风。
(How to banish the summer annoyance? Simply sit quietly in the courtyard. With nothing to clutter the mind, a refreshing breeze naturally arrives by the window.)
3. Agricultural Wisdom
In rural farming communities, an old proverb states: “If Major Heat is not hot, the five grains will not yield crops.”
Sufficient heat and sunshine are crucial for late-season rice and cotton. Farmers historically welcomed these intense thunderstorms, as rain during Major Heat brings essential relief from drought and accelerates the final maturation of crops before the autumn harvest.