Why do most Americans take a shower after they wake up in the morning?

为什么大多数美国人早上醒来之后要去洗个澡？

I'm Chinese. What I know is that nearly all Chinese people take showers at night. Why do Americans take a shower in the morning which drives them to wake up earlier? And I also want to know which countries take a shower in the morning like America, and which countries take a shower at night like China.

我是个中国人。据我所知，几乎所有的中国人都是晚上的时候洗澡。为什么美国人大早上地洗澡呢？这能让他们醒得早一点吗？还有，我想知道哪个国家的人像美国人那样早上洗澡，哪个国家又像中国人那样在晚上洗澡。

获得1.3K好评的回答@Kaiser Kuo

I'm an American-born Chinese who has lived in China for a total of over 20 years, so this is a question that I get all the time. Among everyday habits and, the shower-in-the-morning vs. shower-in-the-evening is one of the real lines of demarcation between Chinese and westerners, and neither my Chinese-born parents (who never lost the evening shower habit even after 40 years in the US) nor my wife, who's from Beijing, ever get tired of asserting¹ the supremacy² of the PM shower. And I've never kicked the AM ablutions habit.

我是个在美国出生的中国人，我住在中国已经20年了，所以这是我一直以来都有的问题。在所有的生活习惯中，早上洗澡跟晚上洗澡成了中西方人的一个真正的分界线。还有我中国出生的父母（虽然呆在美国40多年了，但他们还是一直在晚上洗澡。）跟我来自北京的妻子，都从未改变晚上洗澡的习惯。而我从没改掉在早上洗澡的习惯。

I shower in the morning because it really wakes me up, and provides me with this nice mindless routine³ during which I can think about my day. It also keeps my hair from looking strange. On warmer days where I've conspicuously⁴ sweated during the day I'll take a quick shower and not wash my hair in the evening, but I find that taking a shower right before bed makes it more difficult for me to fall asleep, possibly because I associate showering with wakefulness.

我早上洗澡是因为真的能让我清醒，可以让我认真想想这一天当中毫无头绪的日程。这也能让我的头发看起来不一样一点。天气暖和一点的时候，白天显然出汗多，晚上我就快速地冲个澡然后不洗头，但是我发现睡前洗澡让我更难入睡，可能是因为我已经将“洗澡”和“清醒”联系到一块去了。

I fully understand the Chinese preference for the evening shower. You're clean and comfy, bedding probably doesn't need to be washed as frequently and so forth⁵. But I just need that morning shower to feel fully awake—kind of like that morning coffee!

我完全理解中国人晚上洗澡的喜好。你身上会很干净还很舒服，那样你可能就不用频繁地洗那些床上用品等等。但是我需要早上的沐浴来让我完全清醒——就像早上来杯咖啡一样。