It may or may not be hot in May.
If it is like 90-110 degree hot it is usually best to pick an area or formation that has shade , hike there early, climb until at least 4-5pm and hike back out. If you decide to move from area to area just don't get caught in the hours of 1-3 out in the open. If you do pick a rock with shade, eat lunch,take a nap, etc until 3 or so. I like to freeze a gallon jug of gatorade the day before.
In the summer time there is sometimes people climbing at Discovery Wall, Monolith, Upper Crust late in the afternoon. There are quite a few areas in the new routes list that would be good on hot days and the hikes to get to them are not super long.
If you have not visited the High Peaks yet I would suggest climbing at Spikes Peak. It stays in the shade all of the day, great rock quality, new bolts on all but one route, and super fun routes. There is a whole day of climbing there now. If you have the guide book look up Little Javelina to see the approach. All of the new routes are here in the new routes list. Almost all of the routes are 10a or under.
Crud and Mud has a lot of moderate climbs, Old Man area , and Voyeur Wall would also fit the bill. All three of these areas are in the new routes list.
Have Fun and stay Hydrated