We visited WDW this past June. It was our first trip to Disney during the Summer.
The crowds are double to what we've experienced during early December or mid to late January. However we managed fairly well by avoiding Extra Magic Hours, getting to the parks early and returning to our resort after lunch. We then toured again in the evening once the sun and crowds dispersed. We didn't get done nearly as much as we usually do but we were still able to have a really nice time.
Another thing that slowed us down was the heat. And it is HOT. The heat slows down most people. However we visited the parks in the mornings and then again in the evenings. I enjoyed that the parks stayed open late. The parks are really beautiful after nightfall and have a whole different atmosphere in the dark.
We experienced rain just about every day. Every time it rained we were luckily at dinner. It was a late afternoon or early evening thunderstorm that usually did not last too long. One day, we were headed in to Hollywood Studios and encountered a good downpour. We simply donned our rain ponchos which we had purchased at an outlet store at home and continued walking to the Backlot Express for dinner. By the time our meal was finished, it was only sprinkling and we headed to some indoor attractions. June hurricanes are rare.
The rates are much higher in June. Look at
www.mousesavers.com for ideas on securing discounts. I would visit WDW again in June if it was necessary due to my son's school requirements. For now, we are planning to take my third grader out of school for our January trip to WDW.