Shifting U.S. Cities

KEY CONCEPTS

• New Climate Central analysis shows how warming could make summers in 247 U.S. cities feel like an entirely different part of the country—or the world—by 2100. 

• The average summer warming by 2100 across all 247 cities is 8 °F.

• For many cities, 2100 summer temperatures will be more like conditions farther south—437 miles to the south on average. 

• For 16 U.S. cities, their 2100 summer temperatures have no equivalent on the same continent; their future summers are more similar to locations in the Middle East and Egypt.

Sweltering in Grand Rapids? Imagine how summer feels in Memphis. 

Summers across the U.S. are already warmer than they were in the 1970s. And climate models suggest that summers will only become hotter as heat-trapping emissions continue. Meaning that future summers in Grand Rapids could start feeling more like current summers in Memphis. 

Shifting U.S. Cities
New analysis from Climate Central demonstrates how much hotter 247 different U.S. cities could be by 2100 if emissions trends continue. This analysis projects average summer high temperatures for each decade between 2030 and 2100, and compares them to cities that currently experience similar conditions today (see Methodology for more details on this analysis). 

Shifting cities illustrate how a few degrees of warming during the summer can transport a city to an entirely different temperature zone. 

• Mitchell, S.D. is projected to warm the most by 2100 (11.1 °F), when it will feel a lot more like Wichita Falls, Texas.

• Across the 247 cities included in the analysis, their 2100 analogues are 437 miles south. 

• The average summer warming by 2100 across all cities is 8 °F.

• And 16 U.S. cities have no 2100 analogues on the continent—their future summer conditions are more similar to locations in the Middle East and Egypt.

The six largest cities in the U.S.—with a combined population of nearly 19 million—are projected to experience the following shifts by 2100: 

• New York is projected to warm by 7.6 °F, with summers more like present-day Columbia, S.C. 

• Los Angeles is projected to warm by 5.8 °F, with summers more like Túxpam de Rodríguez Cano, Mexico

• Chicago is projected to warm by 9.1 °F, with summers more like Montgomery, Ala.

• Houston is projected to warm by 6.4 °F, with summers more like Lahore, Pakistan

• Phoenix is projected to warm by 7.2 °F, with summers more like Al Mubarraz, Saudi Arabia

Shifting summer temperatures have the potential to make extreme heat more common, disrupt local ecosystems, introduce new health risks, and strain local economies. 

And this analysis only accounts for daytime summer heat—the hottest temperatures of the day, on average between June-August—and doesn’t incorporate humidity, which contributes to how uncomfortable summer heat can feel. 

POTENTIAL LOCAL STORY ANGLES

How does heat impact cities? 

Climate Central’s urban heat island report analyzed heat island intensity in 159 U.S. cities, and our Climate Change and Human Health Toolkit includes a section dedicated to the impacts of heat. The Future Heat and Vulnerability Map created by the National Integrated Heat Health Information System (NIHHIS) assigns a vulnerability score to each county across the U.S. based on race, income, and other parameters. 

How can adaptation measures protect people from extreme heat?

The EPA maintains a Community Actions Database of measures that communities are taking to mitigate the heat island effect in their area. FEMA has a dedicated page with tools, data, and resources on climate resilience. For state-specific emergency management information, search for your state on the USA.gov site. 

What is being done to protect vulnerable populations?

Check out resources like the EPA guidebook for excessive-heat response, vulnerability-focused stories and projects from ISeeChange, and risk management strategies from the National Integrated Heat Health Information System.

LOCAL EXPERTS 

The SciLine service, 500 Women Scientists or the press offices of local universities may be able to connect you with local scientists who have expertise onurban heat and climate change. The American Association of State Climatologists is a professional scientific organization composed of all state climatologists. 

NATIONAL EXPERTS 

Kaitlyn Trudeau
Data Analyst
Climate Central
ktrudeau@climatecentral.org

METHODOLOGY

We downloaded data from the Coupled Model Intercomparison Project 6 (CMIP6) repository and created time series for each of the stations for which we routinely prepare Climate Matters analyses. For each station, the data consist of daily maximum temperatures estimated by 23 models under the SSP3-7.0 (high CO2) scenario. Temperatures were restricted to June, July, and August. Temperatures for each station for 2060 and 2100 were calculated using the 20 years surrounding that year. We then subtracted the temperature in 2020 to get the change relative to the present. Using ERA5 data, we established a modern summer climate for a list of cities around the world. We then chose those cities whose temperatures corresponded to the focal city’s 2060 and 2100 temperature increases estimated by CMIP6 (+/- 0.2°C). Where possible, cities were restricted to populations of greater than 100,000. We note that several of the 247 local graphics included in this analysis do not include a 2060 location for clarity of visual representation.

Our analysis shows the change from our current climate under the most commonly used high CO2 scenario (SSP3-7.0). In many cases this shows smaller shifts compared with previous studies by Climate Central and others. The smaller shifts occur because we are starting from a climate that has already warmed and because we are projecting change over a shorter period of time (80 years rather than 100 years in some earlier work). Additionally, these prior studies used a climate scenario (RCP8.5) with higher levels of greenhouse gasses and therefore more warming.