This site eo.ucar.edu. has some great kids pages. There are lots of really great facts about weather, you will find stories, activities and safety information such as how to stay safe during a hurricane.
Here is a great site about the water cycle for kids first-school.ws This site contains worksheets, coloring pages and activity pages for young children of 2 upwards.
The wateraid.org site has some good information and we really liked their game to see how much water is used throughout a home here
Make a terrarium and record what you see here A terrarium is a sealed container in which you grow small plants. A small water cycle happens in this environment.
Why not keep a container outside in which you can collect rain and record the amount of rain collected. Also watch what happens to the rain collected once the sun comes out.
To show the three states of water:
Boil water in a kettle or saucepan and record what you see. Pour some of this water into a shallow container and allow to cool. Once the water s cool place into a freezer, show your children what has happened.
Leave the container out of the freezer and see what happens next and record your findings by pictures or words.