A relentless string of heat waves made July 2023 the hottest in St. George’s recorded history.
Daytime highs across the month of July averaged 107.4 degrees in southwest Utah’s largest city. That’s more than 5 degrees warmer than St. George’s historical average for the month and made it the city’s hottest July in history going back to 1893.
All across the state, Utahns felt the heat.
Cedar City experienced its second-hottest July on record, based on average high temperatures. Capitol Reef National Park saw its third-hottest July. In Provo, it was the fourth-hottest July in the city’s history.
Daytime highs in Salt Lake City averaged out at 98.3 degrees — over 4 degrees warmer than its historical average — making this July the city’s third-hottest on record.
At Zion National Park — where crowds of tourists endured punishing heat and park staff illustrated the danger by baking cookies on a car’s dashboard — the average high temperature was a stifling 103.4 degrees. That’s more than 3 degrees hotter than the park’s July average.
John Cecava, a National Weather Service meteorologist in Salt Lake City, said the most unusual thing about July was that temperatures remained so steadily hot day in and day out.
High temperatures in St. George crossed the 100-degree mark every single day in July. For 19 consecutive sweltering days — July 12 through July 30 — residents felt temperatures reach at least 105 degrees, the city’s second-longest streak of 105-degree days on record.
It felt even warmer than normal to Utahns, he said, because overnight low temperatures were also higher than average.
“We haven't had the overnight relief as well as we've had in the past,” Cecava said, “So that's really helped keep our average temperature across the state relatively high.”
On top of the heat, St. George received only 0.02 inches of rain for the entire month, making it the 12th-driest July in city history. It also ranked as the 15th-driest on record in Salt Lake City, 10th-driest in Provo, eighth-driest in Cedar City and fourth-driest at Zion National Park — illustrating the hot, dry trend that’s speeding the return of Utah’s drought this summer.
Utah’s unusually hot July weather was just one piece of a larger story, with heat waves blazing from Mexico to Italy to China. Worldwide, this July became the hottest month in recorded history — a global trend fueled by climate change and greenhouse gas emissions over the past few decades.
Data analysis from Climate Central shows that average summer overnight lows have warmed by 2.7 degrees across the lower 48 states over the past five decades. In Salt Lake City, summer nighttime temperatures are now nearly 8 degrees warmer than they were in 1970.
This type of unrelenting heat without much relief can pose a serious health risk.
“To have prolonged heat for long periods of time, we really get concerned about those who don't have air conditioning, who may be homeless or just don't have access to ways to cool off,” University of Utah Health pediatrician Shana Godfred-Cato said.
Children are especially vulnerable to heat stress, she said, because they can’t always tell when they’re getting too hot or thirsty. So it’s important to check on them, make sure they’re drinking water and cool them off by taking breaks in an air conditioned space or trying a cool shower.
The first week of August has delivered some slight relief with cooler temperatures and rain showers, but the current monsoonal pattern is short-lived — part of the forecast for a weaker and drier overall monsoon this summer.
Temperatures in St. George are expected to soon jump back up near 105 degrees.
“The heat is not done,” Cecava of the National Weather Service said. “It’s still the beginning of August, so it's just another hot month here in Utah.”
Here are how July’s heat numbers stacked up across the state:
St. George
Average high temperature
- July 2023 average: 107.4 degrees (hottest on record, broke previous mark of 107.3 degrees from 2005)
- July historical normal: 101.8 degrees
Average of high and low temperatures
- July 2023 average: 89.8 degrees (ninth-hottest on record)
- July historical normal: 86.8 degrees
Three new daily heat records
- July 17: high of 114 degrees (broke previous record of 112 degrees from 1998)
- July 22: high of 113 degrees (broke previous record of 111 degrees from 2005)
- July 23: high of 112 degrees (tied record from 1996)
Salt Lake City
Average high temperature
- July 2023 average: 98.3 degrees (third-hottest on record)
- July historical normal: 94.0 degrees
Average of high and low temperatures
- July 2023 average: 85.3 degrees (tied for third-hottest on record)
- July historical normal: 81.1 degrees
Seven new daily heat records
- July 16: high of 106 degrees (broke previous record of 103 degrees from 2010)
- July 22: high of 106 degrees (broke previous record of 104 degrees from 2022)
- July 23: high of 104 degrees (tied record from 2003)
- July 23: overnight low of 82 degrees (broke previous record of 79 degrees from 2019)
- July 27: overnight low of 78 degrees (broke previous record of 77 degrees from 2021)
- July 30: overnight low of 79 degrees (broke previous record of 76 degrees from 2016)
- July 31: overnight low of 79 degrees (tied record from 1889)
Provo
Average high temperature
- July 2023 average: 97.9 degrees (fourth-hottest on record)
- July historical normal: 95.2 degrees
Average of high and low temperatures
- July 2023 average: 81.5 degrees (fourth-hottest on record)
- July historical normal: 78.8 degrees
Four new daily heat records
- July 17: high of 105 degrees (broke previous record of 104 degrees from 2022)
- July 23: overnight low of 72 degrees (tied record from 1982)
- July 24: high of 102 degrees (tied record from 2014)
- July 31: overnight low of 73 degrees (broke previous record of 70 degrees from 1989)
Cedar City
Average high temperature
- July 2023 average: 94.8 degrees (second-hottest on record)
- July historical normal: 91.0 degrees
Average of high and low temperatures
- July 2023 average: 77.4 degrees (second-hottest on record)
- July historical normal: 74.0 degrees
Seven new daily heat records
- July 16: high of 102 degrees (broke previous record of 101 degrees from 1960)
- July 18: overnight low of 70 degrees (broke previous record of 68 degrees from 2011)
- July 22: high of 100 degrees (broke previous record of 99 degrees from 2022)
- July 23: high of 99 degrees (tied record from 1996)
- July 24: overnight low of 70 degrees (broke previous record of 67 degrees from 2022)
- July 27: overnight low of 69 degrees (broke previous record of 66 degrees from 1995)
- July 28: overnight low of 66 degrees (broke previous record of 65 degrees from 2003)
