Washington, Baltimore, Philadelphia and much of eastern North Carolina and southeastern Virginia are under extreme heat warnings, the highest level. Highs in these areas are expected to soar to near 100, with heat indexes — a measure of how warm it feels after accounting for humidity — reaching 105 to 110.
Heat warnings — for only slightly less intense heat and humidity — are in effect for a wider area including Boston, New York, Richmond and Raleigh, N.C.
The warmest weather is forecast for Monday and Tuesday, with the potential for triple-digit highs from South Carolina to Maryland. These temperatures are about 10 to 15 degrees above normal for the warmest time of the year.
The National Weather Service describes it as “extremely dangerous and potentially deadly heat.”
At night, temperatures remain much higher than normal, with some places only dropping to around 27 degrees Celsius, which offers little relief.
The Weather Service’s 0-to-4 HeatRisk scale is expected to reach levels 3 and 4 in many areas along the East Coast through Wednesday. And there will be plenty of records, with some locations seeing multiple days — both day and night.
Several record temperatures were already reached on Sunday, including in Washington DC, where temperatures rose to 38 degrees Celsius.
A cold front on Wednesday and Thursday will bring a risk of thunderstorms and bring temperatures closer to normal or even below normal into the weekend, but there are signs that the heat could pick up after that.
Below you can see per city how warm it will be until Wednesday.
Along Interstate 95
Washington — Heat Warning, Maximum 100 Degrees
It reached a record high of 101 on Sunday, and more triple-digit highs are likely throughout the day. Expect only a handful of afternoon storms amid steamy conditions and heat indexes as high as 105 or 110 through at least Tuesday.
- Monday: 100 high
- Tuesday: 100 high / 78 low
- Wednesday: 97 high / 80 low
Baltimore — Heat Warning, High 102
Lots of sunshine mixed with bubbling afternoon and afternoon clouds, and only a slight chance of a storm. Heat indexes of 110 or above are possible Monday and Tuesday.
- Monday: 101 high
- Tuesday: 102 high / 76 low
- Wednesday: 97 high / 78 low
Philadelphia — Heat Warning, Maximum 100
Warm, humid and foggy conditions prevail. Heat indices will rise to 105 or higher on Monday and Tuesday, with nighttime lows not far from 80. An air quality warning is also in effect. Storms with Wednesday’s cold front could be strong.
- Monday: 98 high
- Tuesday: 100 high / 77 low
- Wednesday: 96 high / 80 low
New York City — Heat Warning, Maximum 96 Degrees
A little rain in the area early Monday will do nothing to dampen the heat and could eventually increase humidity. Heat indices will climb to around 100 Monday and Wednesday, while they will climb toward 105 on Tuesday. Storms are likely late Wednesday.
- Monday: 95 high
- Tuesday: 96 high / 77 low
- Wednesday: 93 high / 80 low
Boston — Heat Warning, Maximum 93 Degrees
Plenty of sunshine Monday and Tuesday will bring temperatures into the mid-90s, even near the water. Showers and storms become more likely by late Wednesday.
- Monday: 92 high
- Tuesday: 94 high / 74 low
- Wednesday: 92 high / 75 low
Other locations
Charlotte — No notifications, max 99
Heat indices will be around 100 to 105, with mostly sunny skies and possibly a few isolated showers in the afternoon or evening.
- Monday: 99 high
- Tuesday: 97 high / 75 low
- Wednesday: 95 high / 77 low
Charleston, SC — Heat Warning, high 98
A combination of extreme humidity and very high temperatures is pushing coastal areas in and around Charleston to the limit, with the heat index approaching 115.
- Monday: 98 high
- Tuesday: 95 high / 79 low
- Wednesday: 95 high / 79 low
Roanoke, Va. — No warnings, max 100
Sunny, warm weather is the norm. Slightly lower humidity than further east helps keep the heat index in check, but 100 is warm, dry heat or not.
- Monday: 98 high
- Tuesday: 100 high / 73 low
- Wednesday: 96 high / 75 low
Raleigh, NC — Heat Warning, High 101
The city already set a record this month when it hit 41 degrees on July 5. This week is not as warm, but several days with a temperature index above 41 degrees will take their toll.
- Monday: 101 high
- Tuesday: 99 high / 77 low
- Wednesday: 95 high / 77 low
Hartford, Conn. — Heat Warning, Highest Temperatures in the World
Hartford has had 17 days this year that have reached at least 90, the second-highest total on record. Several more are planned for this week. Heat indexes are headed toward 100.
- Monday: 95 high
- Tuesday: 95 high / 72 low
- Wednesday: 95 high / 74 low