This D.C. Heat Wave Could Be the Hottest and Most Dangerous of the Summer

Washington D.C. could be set to experience its hottest and most dangerous heat wave of this summer, which is already shaping up to be the hottest on record. After hitting 96 on Saturday and then reaching a record high of 101 on Sunday, temperatures in D.C. are predicted to stay in the upper 90s to 100s through Wednesday.

Days of Extreme Heat Ahead

With humidity taken into account, the heat index is expected to climb as high as 110 on Monday and Tuesday. This has prompted the National Weather Service to place a large part of the region under an excessive-heat warning for these two days. This means that the combination of heat and humidity could increase the potential for heat-related illnesses, especially among people working or participating in outdoor activities.

The warnings recommend that people stay hydrated, remain in air-conditioned rooms, avoid direct sunlight, and keep an eye on their neighbors and relatives. It is dangerous to leave young children and pets unattended in vehicles under these conditions.

Breaking Records

Impending record-breaking heat is anticipated over the following days:

• Monday: Forecast high of 101; record high was 100 in 1988.
• Tuesday: Forecast high of 101; record high was 104 in 1988.
• Wednesday: Forecast high of 97; record high was 102 in 1980.

Nighttime won’t bring too much relief as lows are only expected to drop to about 80.

Heat Risk Levels

Parts of the region are anticipated to reach a Level 4 on the National Weather Service’s HeatRisk scale both Monday and Tuesday. This is the highest level and is used to denote long-duration extreme heat with negligible overnight relief. Climate Central’s Climate Shift Index for Monday suggested that such heat is five times more likely due to human-caused climate change.

If D.C. manages to hit 100 degrees or higher on Monday, Tuesday, and Wednesday, it would mean that the city has hit triple digits on four consecutive days. This would tie the longest such streak on record, a feat that has happened previously in 1930 and 2012. However, there’s a possibility that foreseen clouds on Wednesday could keep temperatures below 100.

A Glimpse at the Coming Days:

A cold front is predicted to arrive late Wednesday, bringing the likelihood of showers and thunderstorms and cooling highs back to the 80s and near 90 by the end of the week. Temperatures are expected to climb back into the 90s from Sunday through mid-next week, however, the forecast predicts more tolerable low to mid-90s heat.

A Record-Breaking Summer So Far

This year’s summer in D.C. has been one for the record books. Temperature statistics from this hot summer include:

• The average daily temperature of 81.1 makes this summer the hottest on record thus far, breaking the previous average daily temperature record of 80.9 back in 2010.
• The city has experienced 27 days with temperatures at or above 90 degrees, 10 days more than the average at this point in the summer.
• The city has reached a high of 98 or more on nine days with the most on record in a summer being 13 days in 1930, followed by 11 in 2012.
• The city set calendar-day record highs of 101 on Sunday and 99 on June 23.
• So far this month, the Weather Service has issued six excessive-heat warnings, the most on record in a month. These are issued when heat indexes are expected to be near or above 110. D.C.’s highest heat index this summer has been 111.
• Five days have seen lows of 80 or higher, tied for the second-most on record for a D.C. summer. Monday is expected to make it six. The most on record for a year was seven, recorded in 2016 and 2011.