Just because it’s raining outside, doesn’t mean you can’t enjoy some indoor picnic games!
A great start is to get the girls to decide what they want to eat. These can be made by each in advance or made at the venue.
You could even send recipes to each girl in advance, maybe based on the theme on the party. You then get each of the other girls to guess what the ingredients are or what the shapes of the food are supposed to represent. You could maybe even have the food around the theme of a famous story, which the girls have to piece together. Food is fun and you don’t always need the sun!

