Chinese New Year jumps around the calendar every year, kind of like Easter does. I spent a lot of time trying piecing this together in the past, so sharing a bit about how this works.
There are four main celestial patterns we can see from Earth, and that directly affect our lives and the world around us:
- the rise and fall of the Sun (solar day)
- the rise and fall of the Moon
- the revolution of the Earth around the sun (solar year)
- the revolution of the Moon around the Earth (lunar month and moon phases)
Before there were phones in our pockets and watches on our wrists, there were clock towers and local observatories that kept track of the local time and date. Before all of that, we just watched the sun and the moon. There are even cave paintings of moon phases.
First important pattern: the day
So, it’s really easy to tell if it’s daytime or nighttime, because the sun is either up or it’s not. During the day we have light and heat, and during the night we don’t. Activity makes sense during the day, and some things make sense to do in the morning, and others in the evening.
Second important pattern: the year
The second major pattern that affects us significantly is the solar year. Summer is hot, winter is cold. If you’re not on the equator, there are seasons. As an agricultural society, it’s important to have some understanding of this, because it controls when we plant and harvest.
But it’s hard to tell how far we are into the year and plan things. What is everyone supposed to do, count how many days it’s been since the shortest day of the year?
There’s basically four natural markers. The longest day (summer solstice), the shortest day (winter solstice) and the two equinoxes, where day and night are the same.
(There are actually lots of interesting and very consistent seasonal patterns in nature; bugs and animals emerge from hibernation, birds migrate, trees flower. A whole branch of science studies that (phenology), and all sorts of poems and literature.)
Third important pattern: the lunar month
There is actually a consistent and observable pattern that we can track though: the moon phases. It takes 29.5 days to go from one full moon to another full moon. (The word “month” originally was related to the moon.)
If someone says “I’m having a party at my place 3 days after the full moon”, everyone can figure out when that is.
It’s much easier to track things based on 1) the moon phase, and 2) days after that phase. Every household can do that. And that’s essentially how we end up with the lunisolar calendar.
Some calendars are based entirely off the lunar month, especially in places that don’t have seasons (that’s why Ramadan moves through the year); others are primarily moon-based, but do things to keep the lunar months and solar year in sync (Jewish and Chinese calendars); and others completely abandon any moon observations (Roman/Julian/Gregorian calendar).
So China has had a mix of calendar systems, one that’s tied to the solar year and used for planting, and one that’s tied to the lunar month and used for everything else. Chinese New Year is the synchronization of the lunar months with the solar year.
The actual festival lasts from the new moon (New Year/Spring Festival) to the full moon (Lantern Festival). ~15 days.
(New Year is almost always 2 new moons after the Winter solstice [the shortest day], which is how they sync up. The actual rules are more complicated, but that’s basically the idea.)
The Roman calendar used to work similarly: months were based on the moon, and the year started in the spring. March was the first month. September (sept = 7), October (oct = 8), November (9), December (10) actually made sense once. Winter wasn’t tracked.
But then there was romance (trying to align with the Egyptian calendar, which has 12 months instead of 10) and politics (all months should have 30 days! all months should have 31! we should alternate! July is named after Julius Caesar and so it should have the bigger of the two (31 days)! August is named after Augustus and he’s equally important, so it also should have 31 days!)
That stayed fairly stable until people started making fun of the Christians because their calendar got further and further out of sync with the sun. Easter was no longer in Spring. And that’s when it was reformed and became the Gregorian calendar with all the weird leap year rules. (But notice the changes happen in February, that way March is actually the start of the solar year… just as the Romans did.)
All that said, these things ultimately go back to the sun and the moon and the things we can easily watch.
The fourth pattern: the rise and fall of the moon
This matters if you live near the coast. Tides come in and out, and tidal floods are a thing. It affects us, but it doesn’t affect all of us. Some people track it, some don’t.
More than you ever wanted to know about the calendar.