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0Erinome: Hello dear friends, and welcome back to our show! I'm Erinome.
Enceladus: And I'm Enceladus. It's great to be with you all again.
Erinome: Enceladus, you know, I feel like this autumn was so short. One day I was wearing a T-shirt, and the next day, I had to wear my thick pants.
Enceladus: Haha, I feel the same! It seems like summer just suddenly turned into winter. And you know what? It's not just our feeling. I read some news about it.
Erinome: Oh, really? So, the news says that autumn is really getting shorter?
Enceladus: Yes, exactly. Many places in China are experiencing this. The autumns are "late to arrive and early to leave".
Erinome: Wow. So how do they know that for sure? I mean, how do scientists decide when autumn really starts? It's not just about when we feel cold, right?
Enceladus: That's a great question. It's very scientific. There is a national standard for it. Autumn officially begins when the average temperature for five days in a row is 22 degrees Celsius or lower.
Erinome: Oh, I see. Five days in a row. But the news mentioned something called "sliding average temperature". What does that mean? It sounds a bit complex.
Enceladus: Um, let me try to explain it simply. They calculate the average temperature for a 5-day period. For example, from Monday to Friday. Then they do it again for Tuesday to Saturday, and so on. They "slide" the 5-day period forward.
Erinome: Okay, I think I get it. So they do this to make sure it's not just one or two cold days from some cold air.
Enceladus: Exactly! When they find a 5-day period where the average temperature is 22 degrees or less, and this continues for five days, the first day of that first period is the official start of autumn.
Erinome: That makes sense. It's very careful. So, does autumn start at the same time everywhere in China?
Enceladus: Oh no, not at all. China is a very big country. In cities like Hohhot and Harbin in the north, autumn usually starts in the middle of August.
Erinome: Wow, that's so early! What about the south?
Enceladus: In southern cities like Guangzhou and Nanning, autumn doesn't start until late October or even November. And Haikou has to wait until the end of November!
Erinome: A late November autumn! That's almost winter for us. Are there places with no autumn?
Enceladus: Yes! The news says cities like Kunming, Lhasa, and Xining have almost no autumn because of their special weather. It's like spring all year in Kunming.
Erinome: That's so interesting. So, what happened this year specifically? Was autumn late in many places?
Enceladus: Yes, especially in the south. For example, in Nanjing, autumn started on October 18th this year. That is the latest start in its history.
Erinome: The latest ever? Wow.
Enceladus: And guess what? Its summer was 167 days long this year. That's also a new record.
Erinome: A 167-day summer! That's very long. So this trend of autumn coming late is a real thing.
Enceladus: It is. And it's not just this year. The news compared the average start dates of autumn from 1991 to 2020. Many cities are seeing autumn start later.
Erinome: Which cities are affected the most?
Enceladus: Cities like Zhengzhou, Ningbo, Shenzhen, and Hangzhou have seen autumn get delayed by more than 10 days.
Erinome: More than 10 days! That's a big change.
Enceladus: And for other cities like Beijing, Changsha, and Nanjing, autumn is starting about 5 to 9 days later than before.
Erinome: So that's the "late arrival" part. What about the "early departure"? Is winter coming sooner too?
Enceladus: Yes, that's the other half of the problem, especially in the north this year. Winter came much faster.
Erinome: Can you give me an example?
Enceladus: Sure. In Shijiazhuang, winter usually starts around November 7th. But this year, it started on October 18th.
Erinome: October 18th? That's so early!
Enceladus: It is. Because of that, the autumn in Shijiazhuang was only 31 days long this year. It's their shortest autumn on record. Sad.
Erinome: So, autumn starts late and winter starts early. The time for autumn is getting squeezed from both sides.
Enceladus: You got it. That's why autumn is "shrinking". Data shows this clearly.
Erinome: What does the data say?
Enceladus: Well, comparing the years 1991 to 2020 with 1961 to 1990, the autumn in Hefei became 11 days shorter.
Erinome: 11 days! That's a lot.
Enceladus: And in Beijing, Nanjing, and Changsha, autumn is now 6 to 7 days shorter. Even in cities like Tianjin and Chongqing, it's shorter by 3 to 4 days.
Erinome: This is happening in so many places. So, where in China can people enjoy a long autumn?
Enceladus: Good question. The news says that Southwest China has longer autumns. Places like Sichuan and Yunnan have autumns that last for 70 to 80 days.
Erinome: Oh, that's nice. Which city has the longest?
Enceladus: The city with the longest autumn is Guiyang. It lasts for 83 days on average! Chengdu is second with 78 days.
