Something they do at DS1s school is to find a story and use it as a jumping point for activities. If you can find an appropriate book with something weather based in it, you might be able to come up with activities to do that tie into the story.
I heard of an old collegue who did a whole weather or maybe materials and their properties (waterproof/warm/cool/etc) topic based around the book "Mr Wolfs Week". Its a different weather each day or something. Its been a long time
Staffordshire learning net have a fab geography section. I've used loads for secondary they are bound to have loads of ideas for primary too. They also have a message board used by teachers who may be able to suggest stuff they've used.