I've never said 你好吗 or heard anyone( I mean Chinese )said that to me. I even feel really weird if some foreigners say that to me.( it happens a lot) Generally, I only say something like 早上好 or 晚上好.

In China, it seems rarely to hear that, but they tend to ask if you have eaten like what people do in Taiwan traditionally. However, more young generations prefer to say '' 你好嗎？'' in Taiwan.

I agree with Joy, Chinese rarely use a question to greet people they barely meet. We usually say "你好/您好"(ni hao /nin hao - hello)，"早上好/晚上好"(zao shang hao / wan shang hao - Good morning/Good evening)，or "last name+title+好/你好/您好"(hao / ni hao / nin hao)，比如说"张小姐你好"(zhang xiao jie ni hao - Hello Miss Zhang)，"李叔叔好"(li shu shu hao - Hello Uncle Li) 同意Joy的，中国人很少用问句和生人打招呼。我们一般会说"你好/您好"(ni hao /nin hao)，"早上好/晚上好"(zao shang hao / wan shang hao)，或者"姓+敬称+好/你好/您好"(last name+title+hao / ni hao / nin hao)，比如说"张小姐你好"，"李叔叔好" Generally, we use "xx你好” on someone who is not that close, while using “xx好" on someone we have known for a while. “xx你好”相对于“xx好”来说关系比较生疏，通常如果两个人见过几次面，就不太会说“xx你好”，而是说“xx好”。 "您好"（nin hao）is used on someone we really respect, like merchants to customers，young people to the elders. “您好”（nin hao）是一般对于特别尊敬的人使用，比如说商家对客户，晚辈对长辈。 If you really want to ask someone you know "how are you", it's more authentic to say "最近怎么样？”（zui jin zen me yang - how are you lately）or “最近过得好吗？”(zui jin guo de hao ma - is everything going well recently) 如果真的想问认识熟悉的人how are you，说“最近怎么样？”（zui jin zen me yang）或者“最近过得好吗？”(zui jin guo de hao ma)比较地道。

时常

你好吗 How are you.是中国人看到熟悉的人 或陌生人 经常说的。用来打招呼。