I've taken to wearing long pants even though we've got high heat, high humidity, and lots of shade. But they do provide another barrier to ticks. I'm glad I opted for pants last weekend, it was only in the 70's but the ticks were out in droves. Between me and my hiking partner I wouldn't be surprised if we picked over 100 off of us, most were just crawling on our clothes but I picked off about six that made it to skin, he had closer to a dozen. We had both treated our clothes with permethrin plus we put on some bug repellent at the trailhead. Pants also protect your legs from cuts if you hike on overgrown trail or bushwhack. I'd prefer to wear shorts when its hot though, I've never thought I was cooler in pants.