More than 80 million people are under heat alerts, many living in locations predicted to reach the highest levels of the National Weather Service’s HeatRisk forecast, which rates the danger to human health. Officials are urging residents to stay hydrated, wear light clothing and take breaks in the shade or indoors if they must be out in the heat for an extended period.
“The longevity of dangerous heat forecasted for some locations has not been experienced in decades,” the Weather Service said. “Warm overnight temperatures … will offer little relief, especially to those without adequate or reliable cooling.”
Chicago, St. Louis, Indianapolis, Detroit, Cleveland, Cincinnati, Pittsburgh, Philadelphia, New York and Boston were all predicted to reach a Level 4 HeatRisk at some point during the heat wave. That is the highest level, described as “rare and/or long-duration extreme heat with little to no overnight relief.” Many other cites were forecast to reach Level 3, a level of heat that “affects anyone without effective cooling and/or adequate hydration.”
The heat is expected to surge into northern portions of the Northeast that rarely see prolonged periods of such extreme temperatures in June. Burlington, Vt., could see its hottest three-day stretch in 30 years Tuesday through Thursday, the Weather Service said, with highs in the mid- to upper 90s potentially hotter than a deadly heat wave in 2018. The heat index, which takes humidity into account, is forecast to reach the mid- to upper 90s in Buffalo on Tuesday through Thursday and could surpass 100 in Rochester, N.Y., on Tuesday and Wednesday.
Of the affected cities, Pittsburgh may endure the longest duration of intense heat, rivaling a record-setting stretch in 1994.
The high-pressure heat dome responsible for the dangerous heat could reach a record level of intensity. Research shows that human-caused climate change is enhancing the strength, size and frequency of such events.
Here’s a city-by-city forecast for the heat this week into the weekend.
Near-record highs in the mid-90s to near 100 are expected Tuesday through at least Thursday. The calendar-day records are 97 on Tuesday, 94 on Wednesday and 97 on Thursday. Friday could be slightly cooler but may still come close to the record high of 97. The heat index should reach near 100 to 105 each day. Highs should be closer to 90 this weekend and then in the 80s next week.
The heat peaks Wednesday and Thursday with highs in the mid- to upper 90s, potentially close to the calendar-day records of 96 on Wednesday and 98 on Thursday, with the heat index peaking near 100 to 105 both days. It’s not quite as hot Friday but is still very warm, with highs near 90, before cooler highs in the 80s next week.
Monday and Monday night should be the warmest period, with Monday afternoon highs in the upper 90s to low 100s, the heat index approaching 105 Monday afternoon, and Monday lows only dropping to the mid- to upper 70s. Tuesday through at least Thursday remains rather hot, with highs in the mid- to upper 90s and the heat index peaking near 100. It’s uncertain if similar temperatures will continue Friday and Saturday, or if they’ll cool to the more seasonable 80s to near 90, which is where they are forecast to be Sunday into next week.
Highs are forecast in the mid- to upper 90s Monday through Sunday, possibly reaching near 100 on some days, with the heat index approaching 105 most days. Calendar-day record highs range from 97 to 99 through the period. “Overnight lows will only drop into the 70s, providing little to no relief,” the Weather Service said.
Highs should reach the mid-90s Monday through Thursday, with the heat index reaching the upper 90s to near 100 each day. Calendar-day record highs range from 92 to 96 through the period. Similar heat could continue, but is less certain, Friday through Sunday, before more-seasonable highs in the 80s to near 90 next week.
Highs are forecast in the mid-90s Monday through Friday, and possibly Saturday, with the heat index peaking near 95 to 100 each day. Calendar-day record highs range from 95 to 99 through the period. Cooler highs in the 80s should arrive by Sunday and Monday.
The heat starts to build with highs in the low 90s Tuesday and Wednesday and the heat index reaching the mid-90s to near 100. Hotter highs in the mid-90s Thursday and Friday could come close to the calendar-day record highs of 98 on Thursday and 97 on Friday; the heat index should reach the upper 90s to low 100s both days. Similar heat could continue on Saturday but is less certain, with highs in the upper 80s to near 90 Sunday into next week. If temperatures reach 90 degrees on six consecutive days, it would be the first time they would have done so in the city during June.
The heat starts to build Tuesday through Thursday, with highs in the low to mid-90s and the heat index reaching the upper 90s. More-intense heat is forecast for Friday through Sunday, with daytime highs in the mid-90s to near 100 and the heat index peaking near or above 105 each day. Calendar-day record highs range from 97 to 100 through the period. Similar heat may continue Monday but is less certain. Highs should be closer to 90 the rest of next week.
Highs should reach the upper 90s to low 100s Monday through Saturday, while the heat index should peak near or past 105 most days. Calendar-day record highs range from 95 to 98 through the period. Similar heat may continue Sunday but is less certain; next week, highs cool to the 80s to near 90. The last time the city experienced heat of similar intensity and duration was 30 years ago, when daytime highs reached 95 or higher for six straight days, June 15-20, 1994, the longest such stretch on record, according to the Weather Service.
After reaching a high of 97 and heat index of 101 on Sunday, the city was expecting a high near 95 on Monday and a heat index peaking near 100 again. Tuesday and Wednesday should be a little cooler, with highs in the low to mid-90s, before heating up to the mid-90s to near 100 Thursday through Saturday. Calendar-day record highs range from 99 to 105 through the period. Highs could remain in the mid-90s into early next week.
The worst of the heat is expected Friday through Sunday, with highs in the upper 90s to the low 100s. Calendar-day record highs range from 98 to 101 through the period. The city has a chance to reach 100 for the first time since 2016. Overnight lows in the 70s will offer little relief.
Matthew Cappucci and Jason Samenow contributed to this report.
