Wondering what to do in Plymouth on a rainy day? ☔️ Don’t let the weather stop you exploring! From discovering historical sites, museums, indoor attractions and more, Plymouth is full of great things to do when it’s rainy. 1. @theboxplymouth is an award-winning free to visit museum, art gallery and archive. From immersive exhibitions and child-friendly spaces to an incredible natural history collection, this is the perfect place to spend a rainy day learning all about the history of Plymouth. 2.