The advisory on the National Weather Service’s website screamed “Excessive Heat Warning” in red text, warning of a heat wave smothering the Coachella Valley, the San Gorgonio Pass and the desert portions of San Diego County on Friday and Saturday. The mercury was expected to top out at 120 degrees across the valley.
The message was clear: Don’t go outside.
Temperatures soared higher than normal across much of the nation in June and through the first six months of 2020, putting the country on track for what is likely to be yet another of the warmest years in recorded history.
Each of the 48 contiguous states saw above-normal temperatures during the first half of the year, the National Oceanic and Atmospheric Administration reported in its most recent update on climate conditions in the U.S. and globally.
On Thursday, Idyllwild broke a 20-year-old record for its highest temperature on July 30. By midday Friday, Thermal and Indio were both projected to break or at least come very close to breaking records for the highest daily low recorded on that date, marks that had been set in 1996.
And six of the first seven months of 2020 have seen temperatures well above average in Palm Springs. May led the way, averaging 5.6 degrees above normal.
“Extreme heat will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities,” the National Weather Service’s Southern California excessive heat warning said.
California is heating up
The average temperature across the lower 48 from January through June was 50 degrees, a full 2.4 degrees above normal. It was the eighth-warmest January-to-June period on record.
In California, the year-to-date average daily temperature on June 30 was 55.7 degrees, 2.5 degrees warmer than normal. Even though airplanes were grounded, cars taken off the roads and businesses shuttered in an effort to compel social distancing and stem the spread of the coronavirus, the reduction in greenhouse gas emissions was but a blip. Climate change marches on.
And so, federal experts see the trend of hotter temperatures continuing.
An intense heatwave gripped much of the country in July, and NOAA’s outlook for the next three months shows above-normal chances for warmer-than-normal temperatures. Of the lower 48 states, 38 were hotter than normal in June, setting numerous records and prompting heat advisories from state and federal officials.
In California, this June’s average temperature — 70.5 — was 2.2 degrees warmer than the previous century’s average.
Overall, the country was also dryer than normal in June, said Ahira Sánchez-Lugo, a NOAA climatologist.
The whole world is heating up
In the Arctic, a team with the World Meteorological Organization is working to confirm a temperature reading of 100.4 in Siberia in June. If confirmed, it would be the highest temperature ever recorded north of the Arctic Circle, said Randy Cerveny at Arizona State University.
Globally, five of the warmest years on record have occurred since 2015, and nine of the 10 warmest have occurred since 2005.
“The year 2020 is almost certain to rank among the warmest years on record, with a 35.8% chance of it being the warmest year on record,” said Sánchez-Lugo.
The chances of the year being the second-warmest on record are above 40%, she said. The combined average temperature over land and the ocean across the globe for the first six months of 2020 was less than one-tenth of a degree from being the warmest first six months of the year on record.
The biggest departures in normal temperatures for the nation for the first half of the year were in the Northeast.
“The entire region was 3 to 9 degrees above normal,” said Jessica Spaccio, a climatologist at the Northeast Regional Climate Center at Cornell University.
It was the warmest June on record in Caribou, Maine. Spaccio said it was the third-warmest January to June on record in New Jersey and fourth-warmest in Massachusetts and Rhode Island.
Florida is enduring its warmest year on record.
Conditions have been “just off the charts,” said Brian McNoldy, a senior research associate at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science.
In Miami and Key West, “from one hour to the next, meteorologists are looking to see what record has been broken,” McNoldy said. “It’s hard to keep up with, either some record for the day, for the month, for the year or the year to date. It’s a never-ending stream.”
Other coastal towns throughout the Southeast are experiencing one of their warmest years on record, including New Orleans, Savannah and Cape Hatteras. “With the continued upward trends we’re seeing, it just makes it that much harder to be ‘normal,’ and it makes it that much easier to break record highs because you’re off to kind of a head start.”
The daily lows are heating up
Part of the reason for those warm temperatures is likely the warmer-than-normal sea surface temperatures, McNoldy said. That may be especially true in the warm overnight lows.
“Rather than being able to fall to 76 or 77 degrees at night, if you’re surrounded by an ocean that’s 85 degrees, there’s no way you’re going to cool off that much,” McNoldy said. “And, if the sun comes up and it’s already 84 degrees, you’re just going to go up from there.”
Overnight lows experienced a similar trend, with all of the 48 states averaging at least 1.4 degrees warmer than normal. Nightly minimum temperatures in Connecticut, Massachusetts and New Jersey were 4.5 degrees warmer than the normal average.
Across the country in June, record warm daily low temperature records were set 3,181 times.
The hotter weather has taken a deadly toll. Just 10 days into June, for example, Maricopa County, Arizona, had already reported three heat-related deaths. The nation averages 702 heat-related deaths a year, according to the Centers for Disease Control and Prevention, and scholars expect that number to rise exponentially as temperatures continue to warm.
It no longer surprises Marshall Shepherd, former president of the American Meteorological Society and director of the atmospheric science program at the University of Georgia, to hear heat records are being broken.
It only underscores the critical issues with climate change, he said, such as “how resilient the nation is and how vulnerable populations are going to continue to bear the brunt of this heat and extreme rainfall events.”
Mark Olalde covers the environment for The Desert Sun and can be reached at firstname.lastname@example.org or on Twitter at @MarkOlalde.