24 Solar Terms Calculator
Last updated: 2026-06-25
The 24 solar terms divide the Sun's ecliptic longitude into 24 equal 15-degree segments, running in order from Sohan and Daehan through Ipchun, Usu, and on to the winter solstice, with dates that stay almost constant on the solar calendar.
Enter a year to see that year's 24 solar terms with solar (Gregorian) dates and times in Korea Standard Time. For example, Ipchun (start of spring) falls on February 3-4 every year.
Enter a Year
24 Solar Terms of 2026
Ipchun 2026-02-04
| Solar Term | Solar Date | Day | Time | Longitude |
|---|
Enter a year and click [View Solar Terms].
Solar term times are estimates (for reference) computed with an astronomical approximation. For exact values, check the almanac of the Korea Astronomy and Space Science Institute (KASI).
How to Use
- Enter a year — Type the year you want to look up (e.g., 2026).
- Run the calculation — Click [View Solar Terms] to list all 24 terms in order, from Sohan to the winter solstice.
- Read the results — Check each term's solar date, day, time, and the Sun's ecliptic longitude in the table.
What Are the 24 Solar Terms?
The 24 solar terms (二十四節氣, jieqi) divide the ecliptic — the apparent path of the Sun — into 24 equal segments of 15 degrees to mark the changing seasons. Starting from the spring equinox, where the Sun's ecliptic longitude is 0 degrees, a new term begins every 15 degrees, splitting the year into six terms each for spring, summer, autumn, and winter. Because they are based on the Sun's position, the 24 solar terms are effectively solar markers rather than lunar ones, so their dates stay almost the same each year.
| Season | Solar terms (longitude) |
|---|---|
| Spring | Ipchun (315°) · Usu (330°) · Gyeongchip (345°) · Spring Equinox (0°) · Cheongmyeong (15°) · Gogu (30°) |
| Summer | Ipha (45°) · Soman (60°) · Mangjong (75°) · Summer Solstice (90°) · Soseo (105°) · Daeseo (120°) |
| Autumn | Ipchu (135°) · Cheoseo (150°) · Baengno (165°) · Autumn Equinox (180°) · Hallo (195°) · Sanggang (210°) |
| Winter | Ipdong (225°) · Soseol (240°) · Daeseol (255°) · Winter Solstice (270°) · Sohan (285°) · Daehan (300°) |
Notable terms include Ipchun, the start of spring (around February 4); the spring equinox, when day and night are equal (March 20-21); the summer solstice, the longest day (June 21-22); the autumn equinox, when day and night are equal again (September 22-23); and the winter solstice, the longest night (December 21-22). For more detail, see the guide: What Are the 24 Solar Terms?
Frequently Asked Questions (FAQ)
What date is Ipchun (start of spring) every year?
Ipchun is the moment the Sun reaches an ecliptic longitude of 315 degrees, which falls on February 3 or February 4 every year. Because the exact time shifts slightly each year, the date can vary by about a day, and you can check the precise date for any year with this calculator.
Are the 24 solar terms solar or lunar?
The 24 solar terms are defined by the Sun's position (ecliptic longitude), so they are effectively solar markers. A term changes each time the Sun moves 15 degrees from longitude 0 (the spring equinox), which is why their dates are almost the same every year on the solar (Gregorian) calendar.
Are the solar term dates in this calculator accurate?
This tool computes each term using an astronomical approximation of the Sun's apparent ecliptic longitude and converts it to Korea Standard Time (KST). The dates closely match the official values from the Korea Astronomy and Space Science Institute (KASI), but terms near midnight may differ by a day due to small errors such as Delta T, so treat them as reference values.
Why is red bean porridge eaten on the winter solstice?
The winter solstice is the longest night of the year. Traditionally, red bean porridge was eaten to ward off bad luck and mark the start of the new year. The winter solstice occurs at an ecliptic longitude of 270 degrees, around December 21 or 22.
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Last updated: 2026-06-25