RECORD HEAT
July hottest month ever experienced in Phoenix
Wayne McKelvey sits in the middle of the splash pad at Riverview Park to cool down from triple-digit heat in Mesa on Friday.
Temperatures soared higher than normal across much of the nation through the first six months of 2020 and broke records in July, putting the country on track for what could be another one of its warmest years on record.
After long stretches of hot days and nights, July marked the hottest month on record for the city with a brutal average temperature of 99 degrees, according to a tweet thread from the National Weather Service office in Phoenix.
The average temperature during July 2020, which is calculated by averaging the daily high and low temperature for each day of the month, broke the previous record of 98.3 degrees set in July 2009 and tied in August 2011, NWS said.
High temperatures topped 110 degrees 18 times in July at Sky Harbor International Airport and for seven days mid-month, setting a record for the most days in a year in which the temperature never fell below 90 degrees.
Phoenix was also not the only city in the state to set July records. Litchfield saw its highest average temperature since 1918 and Carefree saw its highest since 1962.
Every one of the 48 contiguous states saw above-normal average 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 United States and around the world.
The average temperature for the United States, excluding Alaska and Hawaii, from January through June was 50 degrees, 2.4 degrees above normal. It was the eighth-warmest January-toJune period on record.
In Arizona, the year-to-date average daily temperature on June 30 was 57.9 degrees, 2.7 degrees warmer than normal.
That figure includes temperatures from across the state, from Flagstaff to Yuma. The average temperature in Phoenix for January to June was 72.1 degrees; in Flagstaff the six month average was 43.7 degrees. Both were above the long-term average.
An intense heatwave gripped much of the country in July, and NOAA's outlook for the next three months shows above-normal chances for warmerthan-normal temperatures.
Of the 48 states, 38 were hotter than normal in June, setting many records and prompting heat advisories from state and federal officials.
In Arizona, this June's average temperature — 76.7 — was 2.3 degrees warmer than the previous century’s average. In Phoenix, the average temperature for June was 92 degrees,
nearly 2 degrees above the average.
Overall, the country was also dryer than normal in June, said Ahira Sánchez-Lugo, a NOAA climatologist.
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 onetenth 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.
In NOAA’s Southwest region, the average temperature was 2.8 degrees warmer than the mean over the previous century, making it the 11th-warmest January to June on record.
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.”
Part of the reason for those warm temperatures is likely the warmer-thannormal 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.
In Arizona, the average minimum temperature so far this year was 43.3 degrees, 2.5 degrees warmer than normal. In Phoenix, the average low was 59.9 degrees for the first half of the year, and 79 degrees in June.
So far, the average nighttime temperature in Phoenix during July has been 87.8 degrees. The average temperature over 24 hours has been over 100 degrees on 16 days during July.
Across the country in June, record warm daily low temperature records were set 3,181 times.
The hotter weather has taken a deadly toll. Through July, for example, Maricopa County had already confirmed six heat-related deaths and officials were investigating 151 additional deaths where heat is suspected. 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.
“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.”
Ahira Sánchez-Lugo Climatologist,
National Oceanic and Atmospheric Administration