Weather is with us every day, good or bad, cold or warm, calm or windy --- we can't escape it. Weather on Earth is dependent on 3 factors - the Sun, water, and the atmosphere. The atmosphere goes up to 74 miles above the earth, however, the weather only reaches a maximum altitude of 9 miles.
The water that we have on Earth is the same water that has been here since the beginning of time. I like to see the look on my students' faces when I tell them that the water they drink and swim in today is the same water that the dinosaurs drank and swam in! If they say, "Oooh, gross!" I tell them they had better never go to Mars or on an extended space mission! :)