Add another impressive heat record to Washington, D.C.’s astonishingly long list over the last four summers.

For over five and a half days ending this morning, the temperature was least 80 degrees in Washington, D.C. This 138-hour streak is the longest on record (dating back to 1871), besting the 128-hour streak of two years ago.

Here are the details:

* At 9 a.m., Monday, July 15, D.C. rose to 83 degrees from 79 degrees the previous hour. At 3 a.m. this morning (Sunday, July 21), it was 80 degrees before falling to 79 degrees at 4 a.m. The total number of hours in between at 80 or higher was 138.

* In 2011, the 80-degree plus streak spanned from 8 a.m. on July 20 through 4 p.m. on July 25, some 128 hours. (More info.).

* During this year’s (2013) streak, three of the nights either tied or broke record high minimum temperatures. July 17 and 18 tied the record high minimum temperatures of 80, and July 19 established a new record high minimum of 81.

The National Weather Service office in Sterling notes that prior to 2011, there had never been a period of longer than two nights when the low didn’t get below 80. We’ve done that in each of the last three summers. In addition to the five-day long 2011 and 2013 streaks, we had a three day streak in 2012 (July 5-7).

List of D.C. summer heat milestones since 2010:

two of the top four hottest Junes
hottest two June days
hottest three Julys
hottest three summers
earliest 100-degree reading in a day
3 longest stretches of temperatures above 80 degrees
longest uninterrupted stretch above 100
most 100-degree days in a month (7)
tie for most consecutive days at 100 (4)
tie for most 90+ days in a year (67)
tie for most 95+ days in a year (28)
At least 50 90+ days for three straight years, first time on record
hottest days so early and late in the season