will continue for the inland pacific northwest excessive heat warnings are often issued when the maximum heat index temperature is expected to be 105 degrees or higher for at least two days while remaining above 75 degrees at night according to the national weather service a heat wave is defined as a period of unusually hot weather usually lasting more than two days jim watsonafp via getty images temperatures are in the 90s but with humidity it could feel over 100 degrees kathryn elsesserafp via getty images a girl cools off in the salmon street springs fountain in portland june 28 2021 jim vaxupphilly kenney phillymayor june 28 2021 if you head out today during the heat emergency in boston remember to stay hydrated drink more water no matter how active you are avoid alcohol and sugary or caffeinated drinks dont wait until youre thirsty to drink heat safety tips pictwittercomdftcdskyp4 city of boston cityofboston june 29 2021 cooling centers are open citywide for all new yorkers tweeted new york city mayor bill de blasio while the causes of death has not yet been determined in each of these cases we can confirm that surrey rcmp is responding to a higher than usual number of deaths since the beginning of the extreme weather conditions surrey rcmp cst for cities in the northeast and northern midwest a heat wave is three or more days of temperatures at 90 degrees or higher you can visit one of our citys cooling sites if youre too hot at home tweeted philadelphia mayor jim kenney on average more people die from heat than any other severe weather including tornadoes hurricanes or flooding according to the national weather service more heat wave safety what to know about heat stroke vs heat exhaustion the pacific northwests heat wave appeared to turn deadly in canada abc news christine theodorou contributed to this report a display at an olympia federal savings branch shows a temperature of 107 degrees fahrenheit june 28 2021 in olympia wash ted s warrenap heat is a silent killer