How does water air and the sun interact to cause weather?
The sun is the driver of all weather. without its energy there
would be no "weather" at all.
The sun heats the land and the waters of earth. when land is heated the air above it expands and rises cooler air rushes in to fill the void. when water is heated it evaporates which rise to form clouds and carries water far and when it cools it falls as rain or snow.
as all the air moves wind is produced and its all a very complex system with much much more to it which is why weather prediction is so bad.
You could also say the water cycle