The temperature rose to 104 degrees just before 3 p.m. Tuesday, tying the highest temperature recorded on that date in 1988. The temperature was the area’s highest since 105 degrees on July 7, 2012. The heat index, which takes into account humidity, rose to 108 degrees. If the heat index rises to 110 degrees, an extreme heat warning will be in effect until 8 p.m.
There have only been 12 other days in Washington state weather history where temperatures have reached 104 degrees Fahrenheit or higher. The highest temperatures on record, 106 degrees Fahrenheit, occurred in 1918 and 1930.
Baltimore also recorded 104 cases, tying the previous record set in 1988. Many other locations in the region also surpassed the 100 mark, including Front Royal, Virginia (102), Martinsburg, West Virginia (101), Dulles International Airport (100) and Frederick, Maryland (100).
Heat in Historical Context
The string of days with temperatures over 100 degrees marks an abrupt departure from recent summers, when the area hadn’t seen temperatures reach 100 degrees in nearly eight years before hitting the 100 mark again on June 22. This summer is only about halfway through, but there have been four days with temperatures above 30 degrees.
A heat watch was issued on Wednesday, which could mark a fourth consecutive day of temperatures reaching 100 degrees (or higher). Four consecutive days of temperatures above 100 degrees would tie the all-time record.
With multiple days of temperatures exceeding 100 degrees, this was the first half of the hottest summer on record for the area. Here are some of the most impressive heat benchmarks so far:
- This summer’s average temperature was 81.5 degrees, beating the previous record of 80.9 degrees in 2010 and making it the hottest summer ever.
- There have been 28 days with temperatures above 90 degrees Fahrenheit so far, 10 days above normal, tied for the second-highest number on record and close to the number of days typically expected around August 6. In 2023, there have been 32 days with temperatures above 90 degrees Fahrenheit.
- Washington, DC, had 10 days with temperatures reaching 98 degrees or higher, tying the all-time record. The most days on record for a summer was 15 in 1930, followed by 14 in 2012.
- The warmest lows on record reached 79 and 81 degrees on Sunday and Monday, respectively. They were followed by two in July, two in June and two in May. There have been no cold records this year.
- The six extreme heat warnings issued by the National Weather Service so far in July are the most recorded in a single month since at least 2006, according to statistics from the Iowa Environmental Mesonet. Extreme heat warnings are issued when heat index temperatures are expected to reach or exceed 110 degrees.
- The highest heat index in the area this summer is 111.
- Including Monday, there have been six days this year when low temperatures reached 80 degrees or higher, the second-most on record. The previous record for a single year was seven days, set in 2016 and 2011. If Tuesday’s low stays above 80 degrees overnight, 2024 will tie 2016 and 2011 for the most on record.
When will the heat wave end?
After a cold front moves through the region late Wednesday, temperatures are expected to return to near-normal Thursday through Saturday. Temperatures may warm up a bit after that, but there’s no sign of temperatures getting back into the triple digits anytime soon. Highs expected Sunday through early next week will mostly be in the low 90s Fahrenheit.
The average high temperature in Washington DC is expected to stay in the 90s for the next 10 days, but will start to drop after that. August is a slightly cooler month than July on average, but it is known to experience some severe heat waves, especially in the first half of the month.
The ongoing heatwave will be shorter than the heatwaves we’ve experienced this summer, but its intensity is unmatched. Climate Central’s Climate Change Index shows that human-induced climate change has made heatwaves three to five times more likely.
