25-26c is the ideal regular maximums for me with mins 16-18c in the cities. This keeps things warm into the evening as well as not stifling in the day.
In fact yesterday was pretty close to perfect (24.3c max, 14.4c min) especially since it was still t-shirt weather at almost 11pm.
I like to see extreme maximums too so higher the better - simply for the experience of it. I wouldn't want 35c everyday of the summer though but not and again it's good to feel it. If yesterday was the main default then that'd do me!