Capris are excellent for this time of year! They let your lower legs still get air and then, when the day ends, you have their warmth when you sit by the bonfire!
Plaid button ups; these will add a little farm pep to your wardrobe, and like the Capris the sleeves can be rolled up or let down depending on the weather. Plus, you can also wear a T underneath it just in case it gets too hot!
Blazer. Of course for Summer you would want to go with a 3/4 sleeve, but what else could you want? You could go chic or victorian, bright or earth toned; the choices are endless!
I hope that you will have a fun late summer!