¿Qué tiempo hace?
Many expressions describing particular weather conditions use hace. To ask, "What is the weather like?" or "What's it like (outside)?" we use the expression, "¿Qué tiempo hace?" This literally means, "What's time doing/making?"
The most common response is "Hace buen tiempo" [It's nice] or "Hace mal tiempo" [It's not nice].
Other more specific weather descriptions describing the state of the sky use Estar or if it is precipitation, it will need a verb to indication action, such as Llover [to rain] and Nevar [to snow]. What do you think Nevada may mean when we refer to the Sierra Nevada mountains? [Hint: most people travel to the Sierra Nevada to go skiing!]