Skip to main content

Main Area


50 cities facing more extreme heat in 2020

  • 50 cities facing more extreme heat in 2020

    September 2020 was the planet's hottest month on record since 1880, according to NOAA’s National Centers for Environmental Information. Extreme heat kills more people every year than all other serious weather events. Dangerously high temperatures can quickly overwhelm victims without much warning and can cause death or grave illness virtually anywhere in the country. Those who work outdoors are especially vulnerable, as are the elderly, the infirm, small children, and pets—especially those that are even briefly left in vehicles.

    Extreme heat disrupts agriculture and puts enormous pressure on utilities and electrical grids. It makes fires much more likely both in the wild and in structures. The hottest days are also a heavy lift for municipalities, which are forced to open cooling centers, corral homeless populations, and put extra emergency responders on the streets.

    There was a time when record-breaking heat was a big deal and when the hottest temperature records stood unchallenged for decades. Today, those records are commonly broken shortly after being set and then quickly broken again. Just as with hurricanes, droughts, and other dangerous weather, extreme heat events are becoming both more frequent and more severe as the effects of climate change become inescapable. Across the country, the hottest days are getting hotter, the coldest days are getting warmer, and summer is encroaching further and further into fall.

    In order to find the cities facing more extreme heat in recent summers, Stacker analyzed data in a July 2020 report from Climate Central, a nonprofit climate communication organization. The report analyzed historical temperature data for 243 cities from NOAA’s Applied Climate Information System over a study period from 1970 to 2019. To select the primary temperature threshold for each city, an “extremely hot day” is defined as the highest 5 degree Fahrenheit increment temperature that occurred at least four days every year during more than half of the years of the study period (1970-2019). Change in the number of “extreme heat” days is based on linear regression. When available, contextual summer weather data from 1970 to 2019 from the National Oceanic and Atmospheric Administration’s Time Series database is provided.

    You may also like: States with the most severe summer weather

  • #50. Cheyenne, Wyoming

    - Increase in extreme heat days: 12.2
    - Extreme heat threshold: 90° F
    - Summer statistics:
    --- Summer average: 64.4° F
    --- Summer maximum: 91.6° F (July 2003)
    --- Summer minimum: 39.4° F (September 1971)

    Cheyenne is no stranger to blazing heat, but the weather there recently has been nothing short of extreme. The region just emerged from its hottest summer in history after temperatures routinely topped 90 degrees in August. Then, on Sept. 8, Mother Nature roared the other way and handed Cheyenne its earliest snowfall on record.

  • #49. Columbus, Ohio

    - Increase in extreme heat days: 12.8
    - Extreme heat threshold: 90° F
    - Summer statistics:
    --- Summer average: 71.4° F
    --- Summer maximum: 91.1° F (July 2012)
    --- Summer minimum: 50.6° F (September 1976)

    The average temperature in Columbus rose by 2.3 degrees between 1951-2012, according to a report by the University of Michigan Climate Center and the Great Lakes Integrated Sciences and Assessment. Columbus got warmer faster than both the country and the world, and temperatures are expected to rise by an additional 3-5 degrees by the middle of the century. In response, the city adopted the Columbus Climate Adaptation Plan, which calls for things like the creation of connected cooling centers.

  • #48. Las Cruces, New Mexico

    - Increase in extreme heat days: 13.3
    - Extreme heat threshold: 100° F

    Located inside the Chihuahuan Desert, the city of Las Cruces is well accustomed to intense heat. In 2017, New Mexico State University nursing students collaborated with the city to create a comprehensive story map for seniors and other vulnerable populations. This year, temperatures there reached the high 90s by April and in May, the city sweltered through eight consecutive days of record heat. By mid-July, the start of the hottest part of the year, Las Cruces was choking under several straight days of 100-plus degree temperatures, with officials scrambling to protect seniors, small children, the indigent, and other high-risk groups.

  • #47. Alexandria, Louisiana

    - Increase in extreme heat days: 13.3
    - Extreme heat threshold: 95° F

    In July 2019, Alexandria began with an intense heatwave and by the middle of the month, the city was canceling events during a stretch of days that earned the highest possible heat index warning of “extreme danger.” The heat index reached or even topped 110 degrees for several days straight, driving the city and much of the region into a weather-induced lockdown.

  • #46. Atlantic City, New Jersey

    - Increase in extreme heat days: 13.4
    - Extreme heat threshold: 90° F
    - Summer statistics:
    --- Summer average: 72.2° F
    --- Summer maximum: 91.3° F (July 2011)
    --- Summer minimum: 53.4° F (September 1978)

    Like much of the country, the South Jersey Shore seems to break its own heat records every summer. On July 23, 2019, temperatures in Atlantic City topped the all-time high. Almost exactly one year later on July 27, 2020, the region was trapped in an extended heatwave that peaked with multiple consecutive days in the high 90s with the heat index moving into triple digits. In places like the Jersey Shore, extreme heat is not only dangerous for people and pets, but it disrupts the critical summer tourism season.

    You may also like: Fastest-warming states in the U.S.

  • #45. Chattanooga, Tennessee

    - Increase in extreme heat days: 13.9
    - Extreme heat threshold: 95° F
    - Summer statistics:
    --- Summer average: 78.0° F
    --- Summer maximum: 97.8° F (July 1993)
    --- Summer minimum: 56.9° F (September 1984)

    Chattanooga is America’s No. 6 fastest-warming city. In Tennessee, where hundreds of thousands of residents are vulnerable to heat-related danger, officials are bracing for an increase from the 10 annual heat danger days it currently experiences to 55 in 2050. Since the dewpoint temperature is rising, the already muggy state is getting muggier in the summers, which increases the length and intensity of mosquito season, and heightens the transmission risk for pathogens like the Zika virus.

  • #44. El Paso, Texas

    - Increase in extreme heat days: 14.4
    - Extreme heat threshold: 100° F
    - Summer statistics:
    --- Summer average: 81.3° F
    --- Summer maximum: 102.6° F (June 1980)
    --- Summer minimum: 60.9° F (September 1976)

    According to the El Paso City-County Office of Emergency Management, “Extreme heat often results in the highest number of annual deaths among all weather-related hazards.” The West Texas border town, located in the Chihuahuan Desert, earned its first excessive heat warning in 25 years in early July as El Paso endured several days straight of triple-digit temperatures that reached 109 degrees at least two days in a row.

  • #43. Birmingham, Alabama

    - Increase in extreme heat days: 14.4
    - Extreme heat threshold: 95° F
    - Summer statistics:
    --- Summer average: 78.5° F
    --- Summer maximum: 98.3° F (August 2007)
    --- Summer minimum: 59.3° F (September 1981)

    Both heat and drought battered Birmingham in the summer of 2019, culminating in the hottest, driest September on record. A year later in July 2020, officials were advising residents to stay indoors once again as heat that was excessive even by the standards of Central Alabama scorched the region. In that part of the South, dangerous heat events not only raise the temperature but also the UV index while increasing the likelihood of dangerous and deadly thunderstorms.

  • #42. Denver, Colorado

    - Increase in extreme heat days: 14.6
    - Extreme heat threshold: 95° F

    According to NPR, Denver residents are becoming resigned to the reality of extreme heat as the new normal—but heat isn’t the only factor in the wild weather that the region has come to expect. During an extraordinary couple of days in early September, Denver experienced both record heat and record snowfall back to back in one 48-hour period.

  • #41. New Orleans, Louisiana

    - Increase in extreme heat days: 14.9
    - Extreme heat threshold: 95° F
    - Summer statistics:
    --- Summer average: 82.0° F
    --- Summer maximum: 96° F (August 2011)
    --- Summer minimum: 68.4° F (September 1975)

    Several Louisiana cities are among those in the United States that are experiencing an increase of at least two weeks of extreme heat days compared to 50 years ago, with a few gaining more than a month of dangerous heat days. New Orleans is getting about 15 more days with temperatures above 95 degrees and a full 28 days when the mercury breaches 90 degrees.

    You may also like: 20 safety preparations for the weather this summer

Trending Now