
I would say keep thier fluids up as that is really important. Also if you are weaning onto dry food I think that is harder for them to eat if they are hot and will need more fluids. If you havent already... try them on a wet food such as Naturdiet this will also aid thier fluid intake.
If you have some fans handy keep them cool using them , I had a litter on the hottest day of the year which stayed for most of the time the puppies were with me. I had a thermometer and used fans to keep them cool but not blow directly on the puppies. If you have windows open make sure flies cant get in.