[ **up: [[Chinese calendar]] | [[Gregorian calendar]]** ] --- # Gregorian–Lunar calendar conversion > The uncertainty in the calculation of the time of moon phases and solar terms decades ahead may be up to a few minutes. If the time of new moon (first day of the lunar month) or solar term is close to midnight, the dates of the relevant lunar month or solar term in the “Conversion Table” may have a discrepancy of one day. Such situation will occur on the new moons on 28 September 2057, 4 September 2089 and 7 August 2097, the Winter Solstice of 2021, Vernal Equinox of 2051, Spring Commences of 2083 and Vernal Equinox of 2084.[^1] - Tables courtesy of Hong Hong Observatory, from 1901 to 2100: https://www.hko.gov.hk/en/gts/time/conversion.htm [^1]: Hong Kong Observatory, *Gregorian-Lunar Calendar Conversion Table*, retrieved 22 December 2024, https://www.hko.gov.hk/en/gts/time/conversion.htm.