I put my adult radiateds outside on sunny days that are above 60. If it’s sunny, they can easily get their body temperature up to 85. Now this is after a night indoors where it’s warm, and I only do this with larger animals.
If its dry, not humid, sunny and not too much wind, it will be okay for a bit, especially if you use a tub of some sort to block some of the wind. Watch carapace temps carefully.