절월·일진 기준
Solar-term month
A month delimited by jie solar-term dates rather than lunar months, used with the day pillar as a basis for traditional date selection.
How did it begin?
The branch changes at twelve jie boundaries, starting with 寅 at Ipchun and 卯 at Gyeongchip, followed by Cheongmyeong, Ipha, Mangjong, Soseo, Ipchu, Baengno, Hallo, Ipdong, Daeseol and Sohan. It sets the month for month break, virtues, officers, paths and phase strength, and need not coincide with a lunar month’s first day.
Calculation rules
The latest jie boundary on or before the date in Korean Standard Time supplies the month branch. The twelve boundaries are Sohan, Ipchun, Gyeongchip, Cheongmyeong, Ipha, Mangjong, Soseo, Ipchu, Baengno, Hallo, Ipdong and Daeseol. Missing necessary previous-year data leaves the value unavailable. The month follows solar terms rather than lunar months. For 2020–2050, it changes on the Korean Standard Time calendar date of each jie boundary, applying to the whole date rather than the exact instant. Missing required solar-term data leaves the value unavailable. WhatDay365 uses the device’s local date, changing the day at midnight (00:00). Lunar and day-pillar conversion supports Gregorian dates 1000-02-13 through 2050-12-31; dates outside this range are not estimated.