Some temperatures mentioned in the article:

100°F = 37.78°C (various mentions. This is body temperature so you can not loose heat effectively in this air temperature.)

110°F = 43.33°C ("many valley communities" low prediction)

115°F = 46.11°C ("many valley communities" high prediction)

117°F = 47.22°C (Nevada weekend peak prediction)

130°F = 54.44°C (death valley prediction, meat can be cooked sous-vide at this point)

Usual summer temperatures in northern/western Europe:

30°C = 86°F (heatwave)

25°C = 77°F (hot weather)

20°C = 68°F (nice summer weather)