Did you know that the Spring Festival falls between January 21 and February 20 in the Gregorian calendar?

January 20 marks the arrival of the "Great Cold" solar term, and February 1 marks the arrival of the 2022 Spring Festival, which is exactly within the "Great Cold" solar term. Another year of Lesser Cold and Greater Cold. "I feel like I haven't done anything yet, how come it's already the New Year!" Many people expressed such emotion when flipping through the calendar.

Poster production: Feng Juan

The Spring Festival in 2020 is on January 25, the Spring Festival in 2021 is on February 12, and the Spring Festival in 2022 is on February 1. Why are the Gregorian calendar times of the Spring Festival always different? Xiu Lipeng, director of the Tianjin Astronomical Society and an expert in astronomical science, explained that the Spring Festival is a festival of the lunar calendar. The traditional lunar calendar adopted by China for thousands of years is actually a lunar calendar. The month is determined by a complete lunar phase cycle, and the year is determined by the time the earth revolves around the sun. The new moon day when the sun and the moon rise almost at the same time is the beginning of each month. The length of each month may be 29 or 30 days depending on the phase of the moon, and 12 months are a year; the solar year is divided into 24 solar terms, and the odd numbers 1, 3...23 are "sections" or "solar terms", and the even numbers 2, 4...24 are "qi" or "zhongqi".

Poster production: Feng Juan

Since the solar year cycle is inconsistent with the number of days in the 12 months of the lunar phase cycle, the ancients used the method of setting "leap months" to solve the problem. The current method of setting leap months in the lunar calendar will add about 7 "leap months" in 19 lunar years. If there is an interval of 11 months between two lunar eleventh months (winter months), no leap month will be added; if there is an interval of 12 months, the first month without a solar term after the previous eleventh month will be set as the "leap month" of the previous month, and no leap months will be added in the following months. The year in which the "leap month" occurs is called a leap year. The position of the "leap month" in each leap year is not consistent. For example, 2014 is a leap September, 2017 is a leap June, and 2020 is a leap April. This method of setting leap months also causes the Spring Festival to come sometimes early and sometimes late.

Usually, the month with the new moon (Spring Festival) closest to the "start of spring" is the first month. As of now, the Spring Festival fluctuates between January 21 and February 20 in the Gregorian calendar, so the 2022 Spring Festival can only be said to come relatively early. The reporter looked through the astronomical calendar and found that in the past 20 years, the earliest Spring Festival was in 2012, which fell on January 23 in the Gregorian calendar, only 2 days later than the earliest Gregorian calendar date of the Spring Festival.

Poster production: Feng Juan

Xiu Lipeng said that whether it is an early Spring Festival or a late Spring Festival, it actually has no impact on our celebration of the Spring Festival. Everyone still prepares New Year's goods, puts up Spring Festival couplets, eats New Year's Eve dinner, and has a great time celebrating the New Year.

Reporter: Chow Yun-kin