Wish I had seen your post in time to be of help - what did you end up doing?
I'll post some suggestions since the weather can often interfere with plans and it might be useful to others to know what else they can do.
Obviously, the easiest to do are anything indoors:
- museums such as the Bargello, Uffizi, Accademia, Medici Chapels...
- churches such as the Cathedral, San Lorenzo, Santa Croce or Santa Maria Novella
- the Last Suppers - there are several across Florence and are an interesting way to see the main convents/cloisters that have fresco Last Suppers pre-dating Leonardo's more famous one in Milan. You can find more info here:
https://www.visitflorence.com/what-to-see-in-florence/last-suppers-in-florence.html
- You could do a San Lorenzo market tour with a cooking class - these are fun and you have lunch included, one that you've learned how to prepare

take a look at this one we did:
https://www.visitflorence.com/what-...es/small-group-cooking-class-in-florence.html
Let me know if you have any other ideas or questions!