Răspuns:
1. He is worried because he thinks it might be cold in York.
2. It will be cold and cloudy on Saturday.
3. The students might go to the National Railway Museum if it rains.
4. On Sunday the weather might be warm and sunny.
5. (who is Anna lol, I'll assume you're talking about Kate) Kate doesn't want to go to the museum because she thinks it will be boring.
6. They might meet Count Dracula if they are lucky.