Unusually strong high pressure is centered over the region today. (PivotalWeather.com)

It’s about as disgustingly hot and humid as it gets this time of year. Washington’s low Tuesday morning only settled at a toasty 79 degrees, and the afternoon high was a scorching 95. Those are both records.

The 95-degree high set early Tuesday afternoon tied the record for Sept. 4, last set in 2008. It marked the latest 95-degree or higher temperature during a calendar year since 2016, when it reached 98, 96 and 95 on Sept. 8, 9 and 10.

As sweltering as it was Tuesday afternoon, the morning low of 79 degrees was even impressive (assuming it holds and is not knocked off by a cooling thunderstorm before midnight). Seventy-nine degrees for a low not only easily passed the previous warmest low for the date of 76 degrees but also tied for the warmest low on record in September. Significantly, it became the latest date Washington has observed a low temperature so warm.

The 72 degree low at Dulles on Tuesday morning was also a record, as was the 73 degrees in Baltimore. Record warm lows also occurred Monday, and more are possible in the days ahead.

In 2018, Washington has now recorded six lows of 79 degrees or higher, which ties for the third most on record. The only years with more are 2016 with eight days and 2011 with nine. Unsurprisingly, seven of the top 10 years on this metric are since 2002, even though the records date to the 1870s.

We have a chance to add to warm-low tallies in the nights ahead as this hot air mass lingers over the next few days. The American GFS (Global Forecast System) model is even spitting out a low of 80 degrees on Wednesday for parts of the D.C. area.


American model forecast low for Wednesday morning.

It is unlikely we’ll test more record high maximum temperatures in the short term. The record high Wednesday is 97 degrees in Washington. That said, the heat is still unusual and persistent. We’ve now notched 41 days hitting at least 90 degrees this year compared with the normal of 36, and we should keep adding to that tally through at least Thursday.


Ninety-degree days through Tuesday. There have been 41 in the District, a few above average annually. (Ian Livingston/The Washington Post)

Correction: The original version of this story said Tuesday’s record high minimum temperature was 67 degrees. It was actually 76, last set in 2012.