Record heat across the US: Summer 2020 in every state
Wildfires, drought, hurricanes, storms, and flooding served as hallmarks for one of the hottest summers in recorded U.S. history. An average temperature of 73.6 degrees Fahrenheit, 2.2 degrees above normal, made the summer of 2020 the fourth-hottest in history. Lower-than-normal rainfall also placed this summer among the driest, placing in the top one-third according to the National Oceanic and Atmospheric Administration. Three states experienced their hottest summers on record, and several more broke their top 10, all experiencing extreme weather.
New temperature records coincided with heat-driven plights across the nation. Americans faced the loss of loved ones, homes, land, and more to record-breaking wildfires that destroyed millions of acres. Wells dried up, and rivers, lakes, and reservoirs faced lower water levels, prompting mandatory and voluntary restrictions in several communities. Drought stressed crops, and heavy rainfall washed them out or opened them to diseases. Hurricanes and tropical storms brought flooding, power outages, fallen trees, and extensive property damage.
Energy demand, triggered by use of power fans or air conditioners in response to blistering temperatures, spiked to 224% above average, the fourth-highest value in 126 years. Air conditioning and other cooling technology proved essential in helping prevent heat-related death and illness, such as stroke, exhaustion, and cramps, during extreme heat.
Climate change threatens to not only bring hotter, record-breaking temperatures but more also heat waves and drought, shortfalls and spikes in precipitation, stronger hurricanes, and larger, more-frequent wildfires. An influx of extreme weather propelled by global warming could also stress water resources, shrink food and crop supplies, and damage infrastructure like roads, bridges, transportation, and more. As the climate continues to warm, Americans could face more summers packed with adverse weather and record heat.
To put the summer of 2020 in historical perspective, Stacker reviewed a National Oceanic and Atmospheric Administration dataset published in October that contained monthly weather data from June to September, and historical temperature averages from 1901 to 2000 for each of the 48 contiguous states. Stacker calculated a percentage change from the historical average and displayed this summer's rank in comparison to the 126 previous years. The temperature database from NOAA’s National Centers for Environmental Information excluded Hawaii and Alaska.
Read on to find out where this record-breaking summer takes its place in U.S. history.
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- Average summer 2020 temperature: 78.0° F (0.3% above historical average; #60 warmest since 1894)
This year brought Alabama its third-wettest six-month period between January and August on record, thanks in part to excessive heat and wet weather. The state faced Tropical Storm Cristobal in early June, which brought extensive rainfall and flooding to some southern parts of the state, according to various news reports. In September, Hurricane Sally caused flooding, power outages, fallen trees that blocked roads, and hundreds of rescues in one county alone. Portions of the state experienced abnormally dry or drought conditions during the summer, however, particularly the eastern portion, where abnormally-dry weather forced farmers to run irrigation for their crops in July.
- Average summer 2020 temperature: 79.8° F (5.1% above historical average; #1 warmest since 1894)
The high-temperature record broke in Phoenix in July at 98.9 degrees Fahrenheit and then again in August at 99.1 degrees Fahrenheit, with high temperatures fueled by years of urbanization and rising greenhouse gasses alongside a lack of rainfall and storm activity from a weaker monsoon season. Increasing heat over the years has raised concerns in the fourth-fastest warming city about growing rates of heat-related illness and death. Tucson and Flagstaff also saw record-breaking temperatures, and some researchers believe that as the climate warms, Arizona will experience more extreme heat and less rain in the future.
- Average summer 2020 temperature: 76.9° F (0.5% below historical average; #79 warmest since 1894)
Most of the state experienced above-average temperatures in July, then faced colder temperatures in August. The capital city of Little Rock, in particular, experienced lower-than-average temperatures for the fourth consecutive summer and zero days with a temperature of 100 degrees Fahrenheit for a second year.
- Average summer 2020 temperature: 75.1° F (5.3% above historical average; #1 warmest since 1894)
Record-breaking heat and dry weather helped fuel the wildfires ravaging California. More than 8,000 blazes, including a notable one at El Dorado Ranch Park caused by a pyrotechnic used during a gender reveal party, scorched more than 4 million acres, destroyed more than 9,000 structures, and killed 31 people. The August Complex fire that ignited in mid-August in northeastern California has since burnt more than 1 million acres alone, making it the first “gigafire” in modern history.
- Average summer 2020 temperature: 65.8° F (4.9% above historical average; #3 warmest since 1894)
Hot and dry weather caused Colorado to receive its first 100% drought declaration for the first time in eight years and experience its largest wildfire in recorded history, which ignited at Grand Junction and torched 139,000 acres. According to the Denver Post, above-normal temperatures and aridity afflicted crops, forests, and water flow in streams and rivers, and smoke from wildfires fumed ozone, which can cause respiratory issues, and other pollutants in Denver. In July, some cities, like Denver and Pueblo, experienced more than 20 days of temperatures of at least 90 degrees Fahrenheit, and Alamosa experienced a record-high and record-low temperature of 92 and 37 degrees Fahrenheit, respectively, on the same day.
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- Average summer 2020 temperature: 70.2° F (5.6% above historical average; #2 warmest since 1894)
Several municipalities enacted mandatory and voluntary water restrictions due to drought caused in part by above-average and sometimes record-breaking temperatures, as well as decreased waterway and reservoir levels. Drought conditions carried into fall, when the state received an increasing number of reports for low water levels in private wells, agriculture water supplies, fire suppression ponds, and streams in the easter portion of the state. According to the NOAA, Hartford experienced 39 days of above 90 degree Fahrenheit temperatures this summer, the most on record.
- Average summer 2020 temperature: 75.3° F (4.7% above historical average; #5 warmest since 1894)
Tropical Storm Isaias ravaged Delaware in August, as the state faced above-average heat and wet weather. The storm caused power outages, $20 million in damages, at least one death, and three tornadoes, one of which beat the state’s longest tornado track at 35 miles. The state also faced heat waves in June and July.
- Average summer 2020 temperature: 81.9° F (2.2% above historical average; #7 warmest since 1894)
High temperatures posed challenges to farmers across the state, although some areas faced drought and abnormally dry conditions, while others experienced wetter than normal weather. According to the NOAA, citrus growers adapted to abnormally arid weather with irrigation, and peanut digging continued in the Panhandle, despite sporadic rain delaying some harvesting and afflicting certain farmers’ peanut plants with leaf spot and white mold. Hurricane Sally, however, drenched fields and destroyed crops in the Panhandle in September.
- Average summer 2020 temperature: 78.3° F (0.8% above historical average; #42 warmest since 1894)
The summer brought dry weather to Georgia, with some eastern areas of the state experiencing moderate drought. Farmers avoided having their corn dry down when an uptick in rain occurred at the end of the summer, but some growers dealt with whiteflies and boll rot in cotton after the precipitation.
- Average summer 2020 temperature: 61.8° F (3.0% above historical average; #18 warmest since 1894)
Idaho began the summer with cooler and wetter weather than normal in the eastern portion in June, but ended it with above-average heat and aridity in August. A low-pressure system and cold netstream brought snowfall to the mountains of northern and central Idaho, as well as parts of Montana, in mid-June. By August, however, some areas in southern and central Idaho experienced “temperatures that either broke records for the month or fell within the top-10th percentile warmest on record,” according to the NOAA
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