Hi Karin
In Brisbane, where the tap water in my place in summer is generally over 25 degrees C, I keep a big bottle of cold filtered water, a cold bottle of mixed stop and a cold bottle of mixed fix permanently in the fridge. I also keep a bottle of mixed stop and a bottle of mixed fix out of the fridge. Then when I am about to start processing, I make up developer with a mix of tap water and cold water, the stop with a mix from the cold bottle and the warm bottle, and the fix with a mix from the cold bottle and the warm bottle. With a thermometer and a bit of practice it is quick and easy to get all working chemicals to a starting point of 19 or 20 degrees C. If you are using the Ilford wash method, you can also easily enough make up a big bottle of wash water at the start of the session with a mix of tap and cold.
The chem temps don't rise much during the processing of a single batch of films (particularly if you can also get hold of a portable AC unit!).
Ian