COMMUNITY RESILIENCE
Waves of Heat
The Science of Extreme Heat
Extreme heat waves tend to stick around longer than they did in the mid-1900s. Data from the 2010s shows that stretches of high heat, often paired with above-average humidity, made the “feels-like” temperature dangerous for longer periods than in previous decades. This lines up with broader climate trends showing that, while weather and temperatures still vary from year to year, North Carolina and the South overall are now experiencing longer and more intense heat waves.
For Southern states like North Carolina, heat waves occur as a result of high-pressure weather systems sitting over the region for an extended period of time. The sun shines, and the high-pressure system acts like a dome or a cap, trapping the heat in place. When this weather pattern continues for multiple days in a row, heat waves occur.
According to The National Centers for Environmental Information (NCEI), this year (2025), July’s preliminary statewide average temperature was 80.4 degrees F, North Carolina’s second-warmest July since 1895. The heat wasn’t just daytime highs; persistently warm nights made it the warmest July on record based on average minimum temperatures.
Mapping Temperature Changes Showing Increasing Heat Severity
The maps below show that in just the last 10 years, the average daily maximum temperature dramatically shifted from a range of 84-88 degrees F in July 2014 to 88-92 degrees F in July 2024. July is usually the hottest month in North Carolina.
Urban Heat Severity has increased in Durham over the past four years.
In Durham County, urban heat islands, caused by more paved surfaces like roads and rooftops, have grown quickly over the past four years. You can see the change in the following image: the 2023 map (on the right) shows far more heat islands compared to 2019 (on the left).
How Heat Hurts
The dangers of heat go beyond just extreme events; sustained high temperatures can disrupt daily life and make it harder for our bodies to function. The effects become especially risky when nighttime temperatures stay above 75 degrees F, because the body struggles to cool down, raising the risk of heat-related illnesses. This risk hits some people harder than others, especially those without air conditioning, proper housing insulation, or those who have to limit energy use to unsafe levels because they cannot afford their utility bills. This situation, known as energy poverty, happens when people can’t afford the cooling or heating needed for safe, healthy living.
Heat-Related Illnesses
Extreme heat can cause a range of health conditions such as:
- Cramps
- Exhaustion
- Heatstroke
- Mental Health Issues
- Diabetes
- Hypertension
Extreme heat can also worsen existing conditions like asthma, bronchitis, and chronic obstructive pulmonary disease, leading to premature deaths. It can also increase rates of suicide, depression, and premature births.
Extreme Heat in the North Central Region
Who is Most Vulnerable?
Everyone experiences heat, but certain groups face greater risks from exposure and are more vulnerable to extreme heat. These vulnerable groups should be centered in discussions about how to deal with heat stress.
Vulnerable groups include:
Elders (people over 65 years old)
Outdoor workers
Menstruating people
People with disabilities
Infants
People with pre-existing medical conditions
Pregnant and nursing people
Incarcerated people
People living with low-income
Staying Cool
If you belong to any of the above-mentioned groups, the following are steps you can take to protect yourself:
Drink plenty of water throughout the day, even if you don't feel thirsty. Avoid alcohol, caffeine, and sugary drinks, which can contribute to dehydration.
Spend time in air-conditioned spaces like public libraries, community centers, or cooling shelters during peak heat hours (usually 10 a.m. to 4 p.m.). If no air conditioning is available, take cool showers or use damp cloths to lower body temperature.
Choose loose-fitting, breathable clothing and protect yourself from the sun with wide-brimmed hats and sunglasses. Avoid strenuous activities during the hottest times.
Recognize heat-related illness symptoms such as dizziness, nausea, rapid heartbeat, and confusion, and seek help immediately if they appear. Check in regularly with elderly neighbors, those with disabilities, or people without air conditioning.
These steps, combined with community support and local heat safety resources explained in the following sections, can help reduce the health risks posed by extreme heat.
Urban Heat, Redlining, and Inequality
The inequalities we see around us are amplified by extreme heat. Black, Indigenous, and People of color (BIPOC), and people with low and moderate incomes often have fewer resources to protect themselves from heat. BIPOC groups are also broadly more vulnerable to extreme heat because of historical and systemic prejudices that limit access to education, better living conditions, and higher paying jobs.
BIPOC and low-income people also tend to live in heat islands as compared to white and wealthier people. This is primarily due to past discriminatory practices like redlining, which denied people access to credit on the basis of their race and socio-economic status. These practices exposed such groups to industrial pollution and less investment in amenities, such as trees and parks. Relatedly, these neighborhoods are especially prone to heat stress and suffer the most during extreme heat events, with little support from the government. A 2020 study of 108 cities in the U.S., including Durham, found that 94% of cities had higher land-surface temperatures in formerly redlined areas compared to non-redlined neighborhoods.
Heat Harms
Extreme heat also harms the environment, animals, and other aspects of human life. Choose a topic below to learn more about how heat hurts.
Ecological Harm
Heat can damage the environment in several ways, including causing more wildfires and outbreaks of forest pests such as the hemlock woodly adelgid (HWA). These forest pests attack and kill both eastern and Carolina hemlocks, the only two hemlock species native to North Carolina.
Heat stress can even cause species extinction, as many creatures, such as fish and reptiles, need external sources to regulate their body temperatures. Extreme heat can make them more vulnerable by making their population unstable, leading to extinction risks.
Threats to Pets and Livestock
Pets and farm animals face increased risk of heat exhaustion and heatstroke when they are left outdoors. About 58.6% of households in North Carolina have pets, and PETA reported that, in just 2024, about 111 pets died due to heat and 388 were rescued from heat-related illnesses. Three of the reported deaths were in North Carolina. As of 2024, Durham County itself has 2,900 cattle and, as of 2023, 3,000 layer (i.e., egg-producing) farms. While we have limited livestock data, farm animals are at a very high risk of extreme heat.
Here are some heat safety checkboxes for pets:
Increased Electricity Usage
When it is hot, we inevitably end up using cooling systems, especially air conditioners, driving up electricity consumption. As more people use AC to cope with extreme heat, the power grid can become overburdened. High temperatures also reduce the efficiency of transmission lines, lowering their capacity to carry electricity to homes and workplaces. This leads to more power fluctuations and a higher risk of blackouts. Such conditions can also worsen the health conditions of people who are already vulnerable to heat, as discussed above.
“As a nurse talking with patients, I find they often do not take heat that seriously, probably because we live in the South where it is hot on a frequent basis. They also might not think it's that big of a problem because heat illnesses are under-identified and under-reported. Most folks do understand that heat can cause serious harm or even death over just a few hours, but it also can be gradual and cause problems over the long term. It can cause organ failure and mental illness from chronic dehydration and stress.”
-Liz Mizelle, PhD, RN
Infrastructure and Transportation Stress
Extreme heat can degrade buildings and create unsafe living conditions. Other structural issues include heat-induced concrete deterioration and structural issues in dams, levees, and other water retention systems. Heat also damages roads. According to a 2017 study, the maintenance and repair costs for roads in the U.S. due to heat are expected to reach $26 billion by 2040.
Extreme heat can also bend or twist rail tracks, overheat vehicles, and cause roadway joints to buckle, creating hazards for transportation workers and travelers.
Tourism
Heat discourages tourism and weakens local businesses. In North Carolina, rising temperatures, even during winter, have led to unpredictable weather and reduced snowfall. This can lead to issues for tourism-related activities that depend on cold weather, like skiing, and can reduce tourism to North Carolina’s beaches and other destinations in the warmer months.
Heat Waves: A Resource Guide for Durham
SCSJ’s Heat Waves resource addresses Durham’s distinct vulnerabilities by providing tailored, data-driven solutions, which supports equity and promotes community resilience.