Outdoor humidity reduction

I live in Central Illinois USA(Zone 5) where summertime humidity levels can run 60-90+% and temperatures 80-100+F. I recently acquired a black sagebrush(A. tridentata) bonsai which, in its native habitat is routinely exposed to similar temperatures and full sun but a much lower humidity. I am familiar with any number of methods to raise humidity around bonsai but am not sure how to go about reducing humidity. I would appreciate any suggestions.

Not really much you can do, safe for putting it in a greenhouse with open ventilation / no irrigation. I find that in daytime sun the air gets really dry. But it also gets a lot hotter.

Thanks, I had a hunch it was going to be like trying to drain the ocean with a fork...