Parts of US Reach Temps “Too Hot for Safe Fan Use” Twice as Often, Scientists Warn

New research shows some US areas are reach­ing dan­ger­ous­ly hot tem­per­a­tures that exceed fan safe­ty thresh­olds near­ly dou­ble the amount from decades past. 

Ana­lyz­ing hourly weath­er data from 1950–1969 and the past 20 years, Duke Uni­ver­si­ty’s Luke Par­sons found more res­i­dents face heat lev­els too high for elec­tric fans to effec­tive­ly cool them.

In loca­tions like inland Cal­i­for­nia, cen­tral Texas and Okla­homa, and along the US-Mex­i­co bor­der, con­di­tions often sur­pass thresh­olds for safe fan use even for healthy young adults. These hotspot areas now expe­ri­ence over 1,000 hours—over 44 days—per year of fan-unsafe heat, ris­ing by 200 hours com­pared to 50–70 years ago.

Elec­tric fans can still be used up to 95°F but lim­its depend on humid­i­ty, age and health. At over 100°F, fans may exac­er­bate heat stress for old­er adults or those on med­ica­tions affect­ing sweat. The vul­ner­a­ble com­mu­ni­ties most impact­ed with lim­it­ed means to cope mer­it resource direct­ing, sci­en­tists stress.