Small pets, especially those in cages or glass tanks, need special care in the summertime when the weather heats up.
First of all, move their habitat out of direct sunlight. Most small pets aren’t big fans of bright lights anyway.
Secondly, if their habitat has a cover, make sure it’s well-ventilated and air circulates well through their living space. You might want to add a small fan nearby to help circulate air (just don’t point it directly at your pet) to help keep them cool.
Provide plenty of fresh water for drinking and play, if appropriate for your pet. Make sure the water is clean and doesn’t attract insects.
If your small pet has an outside habitat, you might want to consider an inside space on the hottest days.