Nearly 200 US cities are seeing more extremely hot days, analysis finds

198 had an increase in the average number of days each year that felt 90F or hotter and 106 cities had an increase in 'danger' days that felt 105F or hotter

Nearly 200 US cities have seen an increase in the number of days each year that soar beyond a heat index of 90F (32.2C) or higher, according to an analysis of the last four decades.

Related: How US cities are scrambling to protect people from extreme heat