Well, no, not necessarily talking about areas adjacent to bodies of water. In the American South, everywhere is humid like that during the summer months and beyond. When we step out the door here in the summer and are hit in the face with humidity of 80-90% we don't consider it a boon. Fungal and bacterial diseases exacerbated by heat and humidity burgeon at that time. Many plants can't tolerate that well and/or people have to constantly spray and treat them to keep down the diseases. It's often not worth it to grow those plants.
Nope, the problem is not with "dry". It's with moist (humid) air. In CA they grow almost everything (the vast majority of this country's fruits and vegetables) in the dry interior valleys of that state. No summer rainfall to speak of, little natural humidity during the summer ... irrigation.
