Well, you will be in the mountains and May can either be very rainy, very windy, very cool (not cold) or may be warm and sunny with temps in the 70s or 80s.
We live about 2 hours from there and we are also in the mountains. This past May, which was unusual, we only had about 5 days that were above 70 and we had about 15' of rain. We camp hosted the entire month and it was good campfire weather almost everyday unless it was raining.
No matter how warm it is during the day, the evenings will most likely be cool or down into the high 40s or low 50s. Since you are from FL, it may be really cool for you.
Whatever you decide, Asheville is a great place to visit and there is plenty to do in the area.
2017 Ford F350 Crew Cab 6.7L 4x4 DRW