We say "What is xx like?" if we want the other person to describe something. For example, if you say "What's your teacher like?", the answer might be: "He's good. He explains things really clearly and patiently. He's a nice guy, too, with a great sense of humour". Likewise, if you ask "What's the weather like today?", I might answer: "It's a bit cloudy and dull, but not too cold. There's quite a strong wind, though." Compare this with the straightforward question, "What's the date today?" which is only asking for one simple fact. (January 9th). When we want one simple fact - just a number, a time, a price, a name - we say "What is...?". But when we want a description ( a full picture, including negative and positive aspects) we say "What is ....like?". I hope that makes sense.

Asking "what something is like" is basically the same as asking "how is it?" It's asking for a description or often an opinion. For example you could ask, "What's your new class like?" This is not asking specific details of the class, like the class name or material, but rather it's asking your feelings of it. Do you enjoy the class? Is it very challenging? In your example with weather, you can answer by describing your opinion of it (it's very pleasant today) or describing the weather itself (it's warm and sunny). "What's the weather?" has something missing and sounds a little unnatural, kind of like asking "What's your new apartment?" Uhhh, it's a place where I live. But if you ask, "What's your apartment like?" It's bigger than my previous place and I love the view!

Because like has different meanings, like=love is the mostly known one. In this question it’s preposition not a verb. here like means “as”