Major Heat (Dashu 大暑): dates, pentads and meaning
The hottest stretch of the year. Taiwan is hot and humid, with frequent afternoon thunderstorms and often typhoons.
Major Heat dates, 2026–2035
| Year | Date | Time (Taiwan, UTC+8) | Month pillar |
|---|---|---|---|
| 2026 | July 23 | 03:13 | still Yi-Wei 乙未 month |
| 2027 | July 23 | 09:04 | still Ding-Wei 丁未 month |
| 2028 | July 22 | 14:53 | still Ji-Wei 己未 month |
| 2029 | July 22 | 20:42 | still Xin-Wei 辛未 month |
| 2030 | July 23 | 02:24 | still Gui-Wei 癸未 month |
| 2031 | July 23 | 08:10 | still Yi-Wei 乙未 month |
| 2032 | July 22 | 14:04 | still Ding-Wei 丁未 month |
| 2033 | July 22 | 19:52 | still Ji-Wei 己未 month |
| 2034 | July 23 | 01:36 | still Xin-Wei 辛未 month |
| 2035 | July 23 | 07:28 | still Gui-Wei 癸未 month |
Times computed by our calendar code (UTC+8); they agree with an astronomical calculation to within about a minute. Between 1901 and 2100, Major Heat always falls on July 22–24. Subtract 8 hours for UTC.
The three pentads of Major Heat
| Sign of the season | When | |
|---|---|---|
| First pentad | Fireflies rise from rotting grass (腐草為螢) | about days 1–5 after Major Heat |
| Second pentad | The earth is damp and the heat is sticky (土潤溽暑) | about days 6–10 after Major Heat |
| Third pentad | Heavy rains come often (大雨時行) | about days 11–15 after Major Heat |
The ancients split each solar term into three pentads (hou 候) of about five days each, and marked them by changes in birds, animals and plants: seventy-two pentads a year. These follow the standard list in Wu Cheng's Yuan-dynasty Collected Explanations of the Seventy-Two Pentads. They were observed in the Yellow River basin, so they do not always match what you see in Taiwan, let alone elsewhere. Some, like hawks turning into doves, record old beliefs rather than biology.
Major Heat in the sky: where the Sun is
The solar terms follow the Sun along the ecliptic: one term for every 15°, and Major Heat is the moment the Sun reaches longitude 120°. In 2027, at Major Heat the Sun sits against the stars of Cancer (drowned out by daylight, of course).
What Major Heat means in BaZi
Major Heat is a qi (氣), or "middle term" (中氣): it falls in the middle of the Wei month (未), so the BaZi month pillar does not change here; it is the same Wei month before and after. Middle terms matter in the calendar for another reason: a lunar month with no middle term in it becomes the leap month.
BaZi months are not counted from the lunar new moon but from the jie terms: Start of Spring, Awakening of Insects, Pure Brightness, Start of Summer, Grain in Ear, Minor Heat, Start of Autumn, White Dew, Cold Dew, Start of Winter, Major Snow and Minor Cold each open a month. If you were born on the day of a jie term, within a few hours of it, your month pillar (and for the Start of Spring, your year pillar too) can shift by one; it depends on the exact time. See solar term boundaries, and for how the month's heavenly stem is worked out, the month pillar.
Look up the solar terms for any year
Pick a year to list the exact time of all 24 solar terms (Taiwan time, UTC+8) and the month pillar each jie term starts. Add a month and day, such as a birthday, to see which solar-term period it falls in and its month pillar. Everything is calculated in your browser.
The times come from the same calendar code our BaZi charts use; for 1901–2100 they agree with an astronomical calculation to within about a minute. If you were born within minutes of a term changing, see solar term boundaries.
The terms before and after
The previous term is Minor Heat; the next is Start of Autumn.
A straight word: solar terms are astronomy; luck is something else
The twenty-four solar terms divide the year by the Sun's position on the ecliptic, and their times can be computed to the second. BaZi uses them to change the year and the month; that is a rule of calculation. A solar term carries no good or bad luck of its own, and no term is a "better" one to be born in: a chart is read as a whole, by its Five Elements and Ten Gods. Everything on this site is for reference and entertainment.
Solar terms set the month; the month sets strength
Enter your birth date for a free Four Pillars chart and see your month element and the balance of your whole chart.
Major Heat: common questions
What date is Major Heat in 2026?
In 2026, Major Heat falls on July 23 at 03:13 Taiwan time (UTC+8); in 2027 it is July 23 at 09:04.
Why does Major Heat move from year to year?
A solar term is the moment the Sun reaches a set longitude, here 120°. A year is about 365.24 days, not a whole number, and leap years reset the count, so the date drifts within a few days. From 1901 to 2100, Major Heat always falls on July 22–24.
What are the three pentads of Major Heat?
First: Fireflies rise from rotting grass (腐草為螢); second: The earth is damp and the heat is sticky (土潤溽暑); third: Heavy rains come often (大雨時行). They follow the standard Yuan-dynasty list.
What does Major Heat do in a BaZi chart?
It is the middle term of the Wei month, so the month pillar does not change. BaZi changes months only at the jie terms.