The BAC 1-11s that we operated in the middle east had a max operating temperature of 50 deg.C and this was with water injection. This came from BAC. After this temp expect to go by road irrespective of runway length. I can remember several aborted take-offs because pilots tried to take-off outside temp limits instead of waiting for it to cool down in the late afternoon or early evening.
I know that these are old technology aircraft but I would assume that the same still holds true for some of the more modern technology aircraft.
I seem to remember that the Gulf Air Tristars were also limited to 50 deg. C. Also British Airways always flew out of Seeb at night during the summer months for the same reason.
Hope this helps.
CC