Oh, I got the best idea ever!
Lolita is sometimes not very comfortable in summer due to the heat. Personally I'm not to fond of wearing a JSK without a shirt under. However, I found a smart solution! A SHORT shirt!!
These short shirts are found in the German national costume! I think it's very smart to keep cool! And you can still keep the little puff sleeves :) Maybe I'll customize one of my old shirts for summer just to try this out! That would be so awesome! ^^ I actually like this neckline with the lovely lace, however it's fully possible too stick to the ordinary lolita collar too if one prefer :)

(pics from ebay.de)