下午好！

Just say it as you walk into a room or meet someone on the street. You can use it as a standalone greeting. You can also add a name or title before it. For example, 老师，下午好 (Teacher, good afternoon) makes you sound very polite. It is a great way to acknowledge someone without starting a long conversation. It is like a verbal wave.

Use this from about 1:00 PM until the sun starts to set. It is perfect for entering a shop or starting a 2:00 PM meeting. If you are texting a colleague after lunch, this is a safe bet. It works well when you want to be more specific than a simple 你好 (hello). It shows you are aware of the time and being thoughtful.

Do not use this once the streetlights come on. By then, you should switch to 晚上好 (Good evening). Also, avoid using it with your very best friends or siblings. It might sound a bit too stiff or 'textbook' for them. With close friends, a simple 'Hey' or 哈喽 (hā lóu) is much more natural. Don't be that person who sounds like a news anchor at a sleepover!

In traditional Chinese culture, greetings were often about food, like 'Have you eaten?' Modern greetings like 下午好 are influenced by Western styles. They became popular as China became more globalized. In big cities like Shanghai or Beijing, you will hear this constantly in business settings. It represents a modern, professional, and polite way of interacting. It is the sound of a busy, productive society.

If you want to sound extra formal, you might hear 午安 (wǔ ān). This is more common in Taiwan or in very elegant settings. It literally means 'afternoon peace.' On the flip side, many people just stick to the universal 你好 (nǐ hǎo). If you are in a rush, a quick nod and 下午好 is the gold standard for being polite but efficient.