Hampton Roads is used to the oppressive heat of summer, and the occasional heat wave, such as last week's, when the swelter was prolonged.
While the temperatures didn’t quite break any regional records, the heat wave came earlier than usual in the season.
“If you start looking at some of the climate records over the last 30 years, this is one of the earlier heat waves that we have seen,” said Jeff Orrock, lead meteorologist at the National Weather Service’s Wakefield office. “It’s going to be one of the rare events where you had this much heat” in June.
The weather service considers a heat wave three or more days with heat indices of at least 105 degrees. The heat index refers to how hot it “feels like” outside, combining air temperature and humidity levels.
Much of the Eastern Seaboard last week was under what officials call a heat dome, an area of high, stagnant pressure that traps hot air underneath.
The Hampton Roads area, as measured at the Norfolk International Airport, hit 105 on Monday, June 23 and peaked at a heat index of 113 on Thursday the 26th, according to NWS data.
Those sensors are located in the shade. For someone standing in sunlight, it could feel about 15 to 20 degrees hotter, Orrock said.
The earliest recorded instance of local heat indices reaching 110 degrees was on June 20, 1964. This year the region hit that on June 26, and was just shy the day prior.
Over the past 20 years, Hampton Roads has experienced 18 multi-day heat waves, with none in 2008, 2009 or 2014, Orrock said.
Scientists overwhelmingly say climate change, accelerated by humans’ continued burning of fossil fuels, is making the planet warmer, as greenhouse gas emissions trap heat in the atmosphere.
Average temperatures across the mainland U.S. have already risen about 60% more than the global average since 1970, according to the Environmental Protection Agency. The number of days above 95 degrees is expected to increase and multi-day heat waves are projected to stretch longer.
Average high daily temperatures in much of Hampton Roads could reach about 78 degrees Fahrenheit toward the end of the century, up from an average 68.7 degrees between 1960-1990, according to federal data. The average for the 2020s is expected to remain about 71 degrees.
Orrock said there is significant year-to-year variability in weather patterns that makes it tricky to identify longer-term trends in the short-term.
Last week’s heat wave brought temperatures about 10 degrees higher than normal during the day and night, compared to the average over the past three decades.
“The heat builds. The temperatures at night don’t drop down as much,” Orrock said. “So you’re not getting much overnight relief.”
Federal officials say extreme heat is the No. 1 weather-related cause of death in the U.S., and also likely the most underreported.
“It’s a silent killer,” Orrock said. “You have to listen to your body.”
Nearly 350 people visited urgent care or emergency rooms with heat-related illness last week in southeastern Virginia, according to the state health department. That can include heat cramps, exhaustion and heat stroke.
“It’s getting worse each year due to rising temperatures and urban heat islands,” Dr. Natasha Dwamena, director of the Hampton and Peninsula health districts, said in a recent news release. “It is important to remember that hot days can impact anyone, but certain conditions can worsen heat-related illnesses. We encourage everyone to make a plan for dealing with extreme heat.”
The urban heat island effect refers to the disparate impact of heat in neighborhoods dominated by surfaces that absorb sunlight, such as asphalt and concrete. Communities with shade-giving trees and reflective surfaces tend to fare better.
