Temperatures compared to normal for the first 10 days of October. (PRISM Climate Group)

Despite widespread cloudiness as well as the calendar date, Washington’s official thermometer reached 80 degrees before the clock struck noon Thursday. The District has now tied the record for the most 80-degree or higher days on record in a year at 136.

Eighty degrees or above on Oct. 11 isn’t super unusual, as the city’s average final 80-degree day tends to come right about now. It is, however, a good 10 or more degrees above the average of 70 degrees for the date.

And this warmth has been incredibly persistent. We’ve now seen nine 80-degree days this month (in the first 11 days, no less), which is more than twice the average of 3.7 over the past 30 years.

The tally of 136 days at or above 80 degrees puts Washington three weeks ahead of the current average for 80-degree days of 117. It ties 1970 and 2007 for the most on record.


Days with highs of 80 degrees or higher by year in Washington. (Ian Livingston/The Washington Post)

The heat milestones keep piling up

The first 10 days of October have kept D.C.'s boiling 2018 at a simmer.

The period Oct. 1 to 10 has averaged an absurd 12.7 degrees above normal. The average temperature of 75.7 degrees is the warmest on record for that period, besting 75.6 degrees in 1941.

Additionally, the record for days with low temperatures of at least 70 degrees, now at 90 days (91 if today holds) continues sailing past the old record of 82 days, set in 2005. The total of four lows of 70 degrees or higher this month, not counting today’s, ties with 1941 for the most on record in October. If today’s low holds, October 2018 is on its own atop the chart for the most lows this warm.

A few of these recent warm lows have set daily records, including the lows Oct. 10 (73) and Oct. 7 (71-tie). If we can stay at or above 67 degrees through the rainfall this evening, we’ll tally another record for this stretch.

Aside from a record high of 86 degrees Oct. 3 at Dulles, afternoon highs mostly haven’t been record-setting, but they have been notable. Recall the high of 90 degrees in Washington on Oct. 4. It wasn’t a record, but it did occur almost three weeks after the average last 90-degree day in Washington and within a week of the latest 90 on record, which occurred Oct. 11, 1919.

Washington certainly isn’t alone in experiencing unusual warmth. It’s a similar story for many locations east of the Mississippi River that are witnessing a record warm start to October.


Temperature rankings over the past week, ending Oct. 10. The reds are warmest or near warmest on record. Over the Plains it is the opposite. (Southeast Regional Climate Center)

With Tropical Storm Michael about to exit the East Coast ahead of a cold front, our weather is finally about to undergo major change. It’s certainly possible we’ve now seen the last 80-degree day and 70-degree low. I’ll keep my fingers crossed for the fans of fall. We’re surely due for some of that!