What others said. A chimney might help you, not so much with lowering temps but especially with battling the wind. On my UDS I got one 1-1/2" downdraft style inlet with ball valve and a 2"x6" chimney and it holds steady like like a champ, even when it's windy as hell. The last big cook I did for a bunch of people was out on a farm with zero trees for windblock. I couldn't believe how the two cookers basically gave the wind the finger and cooked at a steady 250 for hours.
EDIT- you are still learning your pit too, it takes time to get a "program" down for each particular pit. You'll get there.
UDS'-55&16, Akorn, Bar-B-Q Kettle, Drum Grill, miniWSM, cobweb-covered gasser. I'm JD.