Hace or Hay
I have a question. When we talk about weather in Spanish, how do you figure out whether you put "hay" or "hace" before the type of weather? For example, I know that you would say "Hay nubes", not "Hace nubes". Hay nubes = there are clouds. You can also say "hace viento". But why couldn't you say "hay viento"? Because "hay viento" = there is wind. I know that is grammatically incorrect but why/how is it incorrect? Also, hacer means to make/do... So, how do you make wind? I am really confused... Please help!!! 
1 Answer
Here's a list of hace: Hacer is used mainly for current weather and the general "feel" of the weather. The temperature, the state, etc... Hace frío. It's cold. Hace calor. It's hot. Hace viento. It's windy. Hace sol. It's sunny. Hace buen tiempo. The weather is good. Hace mal tiempo. The weather is bad. Hace fresco.
It's cool.
Here's a list of hay: Hay, as you may have noticed, is more specific. It tells the state of the weather outside, many of these can be safely interchanged with hay forms. Hay is more of what you see, and hace is more of the feeling. Hay niebla. It's foggy. Hay neblina. It's misty. Hay sol. The sun is shining. Hay luna. The moon is out. Hay relámpagos. It's lightning. Hay humedad. It's humid. Hay nubes. It's cloudy. Hay lluvias torrenciales. It's pouring. Hay un vendaval. There's a windstorm. Hay granizo. It's hailing. Hay lloviznas.
It's sprinkling.
Here are some with estar: Estar is simply used for general summarizing of the weather. There aren't many estar forms that people use commonly. Está oscuro. It's dark. Está nublado. It's cloudy. Está lluvioso.
It's raining.
And we also have verbs like llover, nevar, tronar, and lloviznar for shorthand writing. These are more for poetic use but many Spanish-speakers use them.
Another link with a similar question. http://www.spanishdict.com/answers/146841/what-is-the-difference-between-hay-and-hace-when-used-to-explain-the-weather/
