Agreed. Riyadh has daily maxima of >40C from May to October, and >45C June-August, peaking about 49C in a normal year. It has low humidity and a little altitude

Agreed. Riyadh has daily maxima of >40C from May to October, and >45C June-August, peaking about 49C in a normal year. It has low humidity and a little altitude (700m), so it is rarely over 50C (shade), but is certainly over 50C in the city, on the street, in the sun. It's relatively easy to walk or run up to 30 minutes on the commute, or after work, when temperatures are up to 43C, without carrying any water. A few years ago, there was more danger from the religious police for wearing running shorts, than from the high temperatures.