I believe HD recommends removing the lowers in the summer, they will increase the temps around the motor and on you. You can vent the lowers but it's about $200+ for the parts.
An oil cooler would be a good addition to the bike to keep temps down in the hotter months.
Cheap fix, take the lowers off.
Also if you haven't do a stage 1 to the bike, SE filter, slip ons (
www.wildpigpipes.com) or any slip on, and get it tuned up for the stage 1 and you'll see more tq and hp and if done correctly a bit cooler running if you add enough fuel. Bikes are lean from the factory as they can get them.