Being Irish weather is always a topic of conversation and so I've gathered some nice art ideas on the topic.
I love a good crayon resist and the rainy rainbow is very striking (top left) https://www.pinterest.com/pin/A5PCmwAQgIIHSz3sbi4AAAA/
Blow painting rain in black and blue is a nice lesson for infants. Just remind them to blow the paint and not suck it! (Top right) https://www.pinterest.com/pin/A43CmwAQgIIHSz3sbi4AAAA/
Lightning strikes over a black paper town. Painting the sky is a nice introduction to tint. Start by painting a strip of black and add a little white as you work down the page. Add lightening in white paint or chalk. (Bottom left) https://www.pinterest.com/pin/A3jCmwAQgIIHSz3sbi4AAAA/
Mixed media storm, I think this could be easily adapted to show a flooded scene. Lots of paper scraps, tin foil and glue! (Bottom right) https://www.pinterest.com/pin/A67CmwAQgIIHSz3sbi4AAAA/
These are more suitable for younger classes.
These crayon resists are so sweet. Umbrellas, wellies and puddles. Water colours were used here but you can use a mix of water and blue paint. Try sprinkling salt on your wet paint and see what happens!! (Left) https://www.pinterest.com/pin/A4TCmwAQgIIHSz3sbi4AAAA/
I love the stormy cloud and these would look great cut out and displayed together. Paint grey clouds and add raindrops and lightening when the paint dries. (Top right)
The rainy window is a nice introduction to printing. Mix a little water with blue paint or use blue food colouring. Use an acetate or the back of a baking tray, lightly cover in paint. Place a white page on top, press lightly and remove. Cut into 4 equal sections and mount on black paper so it looks like a window. Or glue strips of black paper onto the rainy page to look like a window frame. (Bottom right) https://www.pinterest.com/pin/A33CmwAQgIIHSz3sbi4AAAA/