Sanfu Tian (三伏天) Introduction Traditional Chinese Culture

Sanfu Tian (三伏天)‌, often translated as ‌"Dog Days of Summer" (though not identical)‌, is a period in the Chinese lunar calendar known as the ‌hottest, most humid, and muggiest‌ time of the year in China. It typically falls between ‌mid-July and mid-August‌ in the Gregorian calendar.

‌Meaning of the Name:‌ "Fu" (伏) implies lying low or hiding. Ancient Chinese believed that during this period, the intense Yang (heat) energy forces the Yin (coolness) energy to hide underground.
‌Timing Calculation:‌ The exact dates vary each year, determined by the traditional Chinese calendar system:
- ‌Chu Fu (初伏 - First Fu):‌ Starts on the third "Geng" day (a day designated by the Heavenly Stems and Earthly Branches calendar) after the Summer Solstice, lasting 10 days.
- ‌Zhong Fu (中伏 - Middle Fu):‌ Starts on the fourth "Geng" day after the Summer Solstice, lasting either 10 days or 20 days (depending on the timing of the first "Geng" day after the Start of Autumn).
- ‌Mo Fu (末伏 - Last Fu):‌ Starts on the first "Geng" day after the Start of Autumn (Liqiu), lasting 10 days.
‌Weather Characteristics:‌ Expect intense heat, exceptionally high humidity, and "sauna-like" conditions. Strong solar radiation combined with potential rainfall leads to high humidity, making the perceived temperature feel much hotter than the actual air temperature.
‌Health Traditions:‌ Sanfu is a crucial time in Traditional Chinese Medicine (TCM) for ‌"treating winter diseases in summer" (冬病夏治)‌. Common practices include applying "Sanfutie" (medicated herbal plasters on specific acupuncture points), drinking special herbal teas ("Fu Tea"), eating mutton ("Fu Yang"), and consuming bitter foods (like bitter melon). The aim is to expel coldness accumulated in the body, boost immunity, and prevent ailments that worsen in winter (e.g., asthma, arthritis). Emphasis is also placed on cooling down, staying hydrated, and avoiding excessive cold exposure (like very cold drinks/air conditioning).
‌Duration:‌ The entire Sanfu period usually lasts ‌30 days or 40 days‌ (when the Zhong Fu is 20 days long).

‌In short: Sanfu Tian is the peak period of oppressive heat and humidity during the Chinese summer, defined by specific astronomical rules and associated with unique health preservation customs.

三伏天‌是中国农历中一年里气温最高、最潮湿闷热的一段时期。它通常出现在公历的‌7月中旬到8月中旬‌之间。

‌名称由来：‌ “伏”意指阴气受阳气所迫藏伏地下。古人认为这段时间阳气炽盛，阴气被迫潜伏。
‌时间计算：‌ 三伏天的具体日期每年略有不同，由干支历确定：
- ‌初伏：‌ 夏至后的第三个庚日（干支纪日法中带“庚”的日子）开始，持续10天。
- ‌中伏：‌ 夏至后的第四个庚日开始，持续10天或20天（取决于立秋后的第一个庚日出现在立秋前还是后）。
- ‌末伏：‌ 立秋后的第一个庚日开始，持续10天。
‌气候特点：‌ 高温、高湿、“桑拿天”是典型特征。太阳辐射强烈，雨水也可能增多，空气湿度大，导致体感温度远超实际气温，闷热难耐。
‌养生习俗：‌ 传统上，三伏天是“冬病夏治”的重要时机。人们常通过“贴三伏贴”（穴位敷贴）、喝伏茶、吃伏羊（羊肉）、吃苦味食物（如苦瓜）等方法来祛除体内寒气、增强体质，预防冬季易发的疾病（如哮喘、关节炎）。同时，也强调清热解暑、补充水分和避免过度贪凉。
‌时长：‌ 整个三伏天通常持续‌30天或40天‌（当中伏为20天时）。

‌简单来说：三伏天就是中国盛夏最难熬的酷热潮湿期，有特定的计算方法和养生传统。