今天天气真好！

Use it exactly like you would in English. It often starts a conversation or fills an awkward silence. You can say it to a neighbor while waiting for the elevator. You can mention it to a colleague while walking to lunch. It is a verbal 'high-five' to the universe for not raining on your parade.

Use it when the sun is out and the air is fresh. It's perfect for casual encounters. Try it when you first meet a friend at a park. Use it as an opening line in a text message before asking for a favor. It works great at a restaurant if you are sitting by a window. Even in a business meeting, it serves as a light 'pre-game' comment before diving into spreadsheets.

Don't use it if it's actually pouring rain, unless you are being very sarcastic. Avoid it during a serious or somber moment, like a funeral. If someone is telling you about their bad day, mentioning the nice weather might seem dismissive. Also, don't say it to a stranger in a dark alley at 2 AM; that's just creepy, not friendly.

In China, small talk often revolves around shared experiences. While older generations might ask if you've eaten, younger urbanites love talking about the weather. In smog-prone cities, a 'blue sky day' is a huge deal. People will literally stop to take photos of the sky. Saying 今天天气真好！ in Beijing on a clear day is practically a celebration of life.

• 天气不错 (Weather's not bad) - A bit more low-key.
• 阳光真好 (The sunshine is great) - Specifically praising the sun.
• 今天太热了 (It's too hot today) - The inevitable complaint when summer hits.
• 今天挺凉快 (It's quite cool today) - Perfect for a breezy autumn afternoon.