The Twenty-Four Solar Terms: Why the Solar Calendar Lives Inside the Lunar Almanac, and Why It Ties to Farming
The 24 solar terms are seasonal markers tied to Earth's orbit around the Sun, used as a farming guide in the lunar almanac.
Results for "solar terms"
Open datasetThe 24 solar terms
- The solar date each of the 24 terms begins, for every year from 2020 to 2035, computed from solar longitude in Vietnam time.
- 384 rows, 10 columns
- Version 1.1.1, updated 2026-09-30
- Licensed CC BY 4.0, reusable with attribution
Why are there 24 solar terms?
Because each term corresponds to about 15 degrees of ecliptic longitude, and 360 degrees divided by 15 equals 24.
From the article “What is Tiết khí?”
Traditional systems
StartName your child
Name ideas that suit the baby's Bát Tự chart, each with a reason.
What is Tiết khí?
Solar terms are 24 markers dividing the year by the Sun's position on the ecliptic, used in East Asian calendrics to determine seasons and festivals.
Dong Chi and Tết Đông Chi: the shortest day of the year, che troi nuoc, ancestor worship, and why Dong Chi was once the year's starting point
Dong Chi is the 22nd solar term and the shortest day of the year. For the Chinese community it is Tết Đông Chi, a time for che troi nuoc and ancestor worship.
What Is Tiểu Thử (Minor Heat)? When Does It Begin and What Customs Are Associated With It?
Tiểu Thử usually begins on July 7 and opens the Mùi month. Start times for 2025 to 2030, the meaning of its name and what classical books record.
Tam nguyên and the 18 Ju of Qimen: How to Derive the Ju Number from Solar Terms According to the Source Texts
Tam nguyên splits each solar term into three five-day spans, each with one Kỳ Môn cục. The 24-term table follows the Hiệp kỷ biện phương thư.
Which month is good for having a child? Why does Bát Tự change months by solar terms while Tử Vi uses lunar months?
No birth month is best for everyone: Bát Tự reads the month by solar terms, Tử Vi by lunar months, and folk sayings on good birth months lack a firm basis.
What Is Hàn Lộ Solar Term, When Does It Begin, and What Customs Does It Have?
Hàn Lộ is the 17th of the 24 solar terms, beginning around October 8 when the Sun reaches 195 degrees. Learn its meaning and customs.
Building the Four Pillars of BaZi from birth date and time: the year pillar changes at Lập Xuân, the month pillar changes at the solar term, the day pillar follows the 60-cycle, and the hour stem is derived from the day stem
BaZi's Four Pillars from birth date and time: the year pillar turns at Lập Xuân, the month at solar terms, the day runs the 60-cycle.
What Is Đại Hàn, When Does It Begin, and What Customs Are Observed?
Đại Hàn is the last of the 24 solar terms, at solar longitude 300 degrees and lasting about 15 days. Here its calculation, customs, and meaning are explained.
When Does Thu Phân Begin and What Customs Mark It? A View from Sui Shi Guang Ji and Calendrical Science
Thu Phân, the 16th of the 24 solar terms, begins on 22 to 24 September as the Sun enters the Thọ Tinh station. Its calendar roots and customs, explained.
What Is Tiểu Mãn, When Does It Begin, and What Customs Come With It?
Tiểu Mãn, the 8th solar term, begins on 20 or 21 May when the Sun reaches 60 degrees longitude. In 2026 it starts at 07:28 on 21 May, Vietnam time.
What Is Tiểu Hàn (Minor Cold)? When Does It Begin and What Customs Come With It?
Tiểu Hàn is the 23rd of the 24 solar terms, at solar longitude 285 degrees. It starts on January 5 or 6, opens the Sửu month and lasts about 14.7 days.
When Does Lập Hạ Begin and What Customs Come With It?
Lập Hạ, the 7th solar term, opens summer when the Sun reaches 45 degrees of longitude, usually on 5 or 6 May. How it is calculated and its customs.
What Is Tiểu Tuyết (Minor Snow), When Does It Begin, and What Customs Come With It?
Tiểu Tuyết is the 20th of the 24 solar terms, usually beginning on 22 November in Vietnam time; it is the mid-month qi of the month of Hợi (10th lunar month).
How Ba Tu Major Cycles Are Set: Why They Run Forward or Backward by Gender and the Yin Yang of the Year Stem, How the Starting Age Is Counted from Days to the Nearest Solar Term (Three Days to One Year), and How to Read a Ten Year Major Cycle Together with the Annual Cycle Against the Useful God
Ba Tu major cycles are set by gender and the yin yang of the year stem, with starting age counted from days to the nearest solar term at three days per year.
The Origin and Meaning Behind the Name "Tết Nguyên Đán"
The name "Tết Nguyên Đán" comes from "Tiết," a marker in the agricultural calendar, and "Nguyên Đán," meaning the first morning of the new year.
Is the Lunar Calendar Science or Superstition? Two Layers of One Calendar, the Computable Astronomy and the Day-Selection Layer Added Later
Lunar dates, leap months and solar terms are verifiable astronomy, while auspicious days and lucky stars are a later day-selection layer.
Thanh Minh Festival and the Distinctive Grave-Visiting Custom of the Vietnamese
Thanh Minh in Vietnam is mainly an occasion to remember ancestors by visiting graves, unlike China where spring outings also occur.
The Vietnamese Lunar Calendar Is Actually a Lunisolar Calendar: Why the Shortened Name 'Lunar Calendar' Causes Misunderstanding
The Vietnamese lunar calendar is actually a lunisolar calendar combining the moon's phases and Earth's orbit around the Sun.
Is an Online Bát Tự Chart Accurate and Should You Use It? How to Check and the Limits You Need to Know
Online Bát Tự charts build fast, but accuracy hinges on birth hour data, time zone, and solar terms. Know when to trust them and when a reader must verify.
What Makes the 2027 Lunar Calendar Special and How to Look Up Dates Correctly
Lunar calendar 2027: year of Đinh Mùi, Tết on Saturday 6 February 2027, no leap month. Key dates, solar terms, and how to look up dates and convert Can Chi.
How to Determine Yang Dun or Yin Dun, the Ju Number, and Zhi Fu and Zhi Shi in Qi Men Dun Jia
Solar terms set Yang Dun or Yin Dun, and the fu tou day sets the yuan. This guide covers ju numbers, super spirit and qi continuation, Zhi Fu and Zhi Shi.
Converting Lunar Dates to Solar Dates: What the Calculation Is Based On, and Why It Is Not a Fixed Addition and Subtraction Table
Lunar to solar conversion uses no fixed addition table. It relies on the new moon point, major solar terms and legal time zones, so it differs year by year.
What Is Mang Chủng Solar Term, When Does It Begin, and What Customs Are Observed?
Mang Chủng is the 9th of the 24 solar terms, usually starting around June 5 or 6 as Tiểu Mãn ends. Its meaning, calendar role, and customs explained.
What Is Vũ Thủy, the Rain Water Solar Term, When Does It Start, and What Customs Does It Have?
Vũ Thủy, second of the 24 solar terms, marks damp rain and warming soil after winter. This explains its dates, meaning, and folk customs.
What Is Lập Thu, When Does It Begin, and What Customs Come With It?
Lập Thu, tiết khí thứ 13, đánh dấu chuyển hạ sang thu. Bài giải thích cách tính ngày, ba hậu, gốc tích trong Tuế thời quảng ký và tục lệ.
What Is Bạch Lộ (White Dew), When Does It Begin, and What Customs Come With It?
Bạch Lộ (White Dew), the 15th solar term, starts around 7 or 8 September as night vapour condenses into white dew, marking mid-autumn in the calendar.
Why two calendars give different lunar dates for the same solar day, and where time zones come in
Two calendars can give different lunar dates for the same solar day because they use different legal time zones, such as Vietnam at UTC+7 and China at UTC+8.
What Is Đại Tuyết, When Does It Begin, and What Customs Are Observed?
Đại Tuyết, the 21st solar term, begins at solar longitude 255 degrees, usually on 7 December, opening the Tý month. Start times 2025 to 2030, Vietnam time.
What Is Kinh Trập, When Does It Begin, and What Customs Are Associated With It?
Kinh Trập, the third of the 24 solar terms at solar longitude 345 degrees, usually begins March 5 or 6. Origin of the name and start times for 2025 to 2030.
What Is Lập Đông, When Does It Begin, and What Customs Come With It?
Lập Đông is the 19th of the 24 solar terms, marking the start of winter and usually falling on 7 or 8 November each year.
What Is Đại Thử (Major Heat), When Does It Begin, and What Customs Come With It?
Đại Thử, the 12th solar term and mid-term of the sixth lunar month, begins when the Sun reaches 120 degrees, on 22 or 23 July. Start times 2025 to 2030.
When Does Hạ Chí Begin and What Customs Does It Have?
Hạ Chí begins when the Sun reaches 90 degrees of solar longitude; from 2012 to 2043 it falls on 21 June, Vietnam time. Start times 2025 to 2030, old customs.
The Lunar Leap Month: Why It Exists, How It Is Calculated, and Why One Lunar Day in a Leap Year Corresponds to Two Solar Days
How a lunar leap month is determined, why leap years exist, and why one lunar day in a leap year corresponds to two solar days.
When does Cốc Vũ begin and what customs come with it? Calculation and meaning in the traditional calendar
Cốc Vũ, the sixth solar term beginning 19 or 20 April, marks the rains that feed the rice. Its calculation, meaning and folk customs are explained.
When Does Lập Xuân Begin and What Customs Mark It?
Lập Xuân, the first solar term of the year, falls on 3 or 4 February (4 February in 2026). How it is calculated, why it changes the year, and its customs.
What Is Sương Giáng (Frost's Descent), When Does It Begin, and What Customs Are Observed?
Sương Giáng 2026 begins at 16:39 on 23 October, Vietnam time. The 18th solar term, mid-term of the ninth lunar month: dates, three pentads, customs.
When Does Xuân Phân (Spring Equinox) Begin and What Customs Mark It?
Xuân Phân, the fourth of the 24 solar terms, starts on 20 or 21 March in Vietnam time. Exact dates to 2030, its three pentads and the customs around it.
When does Xử Thử (處暑) begin and what customs are associated with it?
Xử Thử is the 14th of the 24 solar terms, usually beginning around August 23, marking the retreat of heat and the arrival of autumn.
The 24 solar terms
The solar date each of the 24 terms begins, for every year from 2020 to 2035, computed from solar longitude in Vietnam time.
Start moments of the 24 solar terms, 1900 to 2100
The start moment of each solar term across 201 years in Vietnam time, with the solar longitude of the mark and a flag for moments falling close to midnight.