If they don't have access to water, then you need to monitor the temperatures. I like it when it's around 75-85 in the shade, which brings up another consideration... you need to have an area with shade, preferably closer to the ground (where it will be cooler).
well its like high 90's low 100's here in Texas and i let my turtle out for like 5 mins because it was really hot didnt know if that was enough time or to much