Temperatures are expected to reach the upper 90s again Wednesday, leading to a third consecutive day of heat warnings.
Meanwhile, nights have been muggy. This summer has seen several days with lows above 80 degrees for the first time in five years. Before 2000, such warm nights were extremely rare.
A combination of hot days and muggy nights marked the start of the second-hottest summer on record.
The heat may ease on Friday, but it won’t last long. Hot weather will return over the weekend and become even more intense next week.
Human-caused climate change has made recent heatwaves in the Washington, D.C., area twice as likely, according to the Climate Change Index from science communications company Climate Central.
The second hottest summer on record
According to meteorological definitions, summer began on June 1. Since then, the current average temperature is 80.5°C, second only to 2010’s 80.8°C as the hottest year to date. Rounding out the top five are 1994 (80.1°C), 2011 (79.4°C), and 2012 (78.9°C).
Since January 1, this year has also been the second-hottest year on record, with an average temperature of 58.7°C, behind only 2012’s 59.3°C (which then became the hottest year on record). The United States has also experienced its second-hottest year on record so far.
Unusually high afternoon temperatures have become the norm since heating began in mid-June. The average temperature since June 1 has been in the 90s, the third-highest on record after 2010 (90.4) and 1994 (90.6).
The 22 days with high temperatures reaching 90 degrees or higher are eight more days than normal in previous years. Typically, we don’t see that many days with temperatures above 90 degrees until late July. Last year, there were only 10 such days by this point.
In addition to consecutive days with temperatures above 90 degrees, there were nine days with highs above 97 degrees, including the first time the temperature topped 100 degrees since 2016. To date, only nine days in 1991 and 12 in 2012 have exceeded that number on record.
It’s the fifth straight day with a high of 97 degrees or higher, and likely will be the sixth on Wednesday, the second-longest streak on record behind a seven-day streak set in 1953.
This summer’s low temperatures are the second-warmest on record. The average low of 71 degrees is just slightly lower than the warmest night ever, which was 71.2 degrees in 2010.
There have already been four nights on record with lows above 80 degrees Fahrenheit, three of which occurred between Saturday and Monday, with another likely on Wednesday for a total of five. The most nights with lows above 80 degrees Fahrenheit on record in a single year is seven, the last time this occurred was in 2016.
The current heat wave, which began on July 4, will likely end on Friday, when clouds and tropical moisture pulled north by the remnants of Hurricane Beryl will briefly blanket the region, bringing some cooler temperatures (but not humidity). Due to the worsening drought, rain is quite likely, but highs will stay below 90 degrees. However, the forecast also includes the possibility of dry spells and warmer temperatures.
After that, highs above 90 degrees are likely for at least the next two weeks. Hot weather is expected through July 27, with an average high of 90 degrees. But computer models are predicting higher than normal temperatures, likely reaching the 90s and even near 100 degrees at times.
Jason Samenow contributed to this report.
