The summer of 2025 has made a strong debut in the United States with the arrival of a powerful “heat dome” covering the Midwest and East Coast regions, posing a dangerous weather situation of intense heat and high humidity for millions of people in Nebraska, Illinois, Iowa, and Wisconsin.
According to a report by meteorologist Tom Kines from AccuWeather, a weather company cited by the Associated Press, many people have been wondering where summer has been in recent weeks. He warned that despite actual temperatures hovering around 90 degrees Fahrenheit (approximately 32 degrees Celsius), the combination of humidity could make it feel like as high as 110 degrees Fahrenheit (approximately 43 degrees Celsius).
The National Weather Service in the United States explained that a heat dome is a climate blocking phenomenon formed by a high-pressure system in the upper atmosphere, trapping heat and moisture near the surface and hindering air circulation, leading to a continuous rise in temperatures. Predictions indicate that this heatwave will stretch from the Great Lakes to the East Coast, with daytime temperatures ranging from 90 to 99 degrees Fahrenheit (approximately 32 to 37 degrees Celsius) and nighttime temperatures around 75 degrees Fahrenheit (approximately 24 degrees Celsius), with little respite from the heat.
Furthermore, a warm and moist airflow from the Gulf of Mexico continuously moving northward is exacerbating the sultry weather conditions.
In states like Iowa and neighboring agricultural regions, the humidity levels are further increased by the phenomenon known as “corn sweat.” Plants under extreme heat transport water to their leaf surfaces, which evaporates into the air through transpiration. Although this is a localized phenomenon with a smaller impact compared to moisture from the Gulf of Mexico, it still contributes significantly to the oppressive heat in specific areas.
According to forecasts from the National Weather Service, temperatures in many areas will approach record highs in the coming days, with Denver reaching 100 degrees Fahrenheit (approximately 38 degrees Celsius) on Friday, Chicago expected to hit 96 degrees Fahrenheit (approximately 36 degrees Celsius) on Sunday, and Washington D.C. and New York reaching 99 degrees Fahrenheit (approximately 37 degrees Celsius) and 96 degrees Fahrenheit (approximately 36 degrees Celsius) respectively next Tuesday.
During the weekend, the Weather Service’s risk index shows that Nebraska and Kansas will be at “Level 4” of the highest risk on Saturday, expanding to Iowa, Wisconsin, Missouri, and Illinois on Sunday. This indicates that without adequate cooling equipment or sufficient hydration, residents’ health could be at risk.
In high humidity environments, the body’s sweating mechanism is less effective in evaporating moisture, leading to an accumulation of heat inside the body and an increased risk of heat exhaustion and exacerbation of chronic illnesses. According to the Centers for Disease Control and Prevention (CDC), when the heat index exceeds 105 degrees Fahrenheit (approximately 41 degrees Celsius), individuals are already in a dangerous zone.
The National Athletic Trainers’ Association (NATA) advises that special attention should be paid to symptoms including confusion, seizures, delayed reactions, vomiting, diarrhea, headaches, weakness, and body temperatures above 104 degrees Fahrenheit (approximately 40 degrees Celsius), where immediate cooling and medical attention are necessary.
The most effective first aid measure is “immersion in ice water.”
Other recommendations include wearing loose, light-colored, breathable clothing; applying sunscreen every two hours; staying in air-conditioned spaces and avoiding sun exposure; never leaving children or pets alone in vehicles; carrying an ample amount of water, with outdoor workers advised to hydrate with about 240 milliliters every 20 minutes; replenishing electrolytes when necessary but avoiding high-sugar or high-caffeine beverages; and paying attention to weather alerts, heat index, and UV index.
The U.S. government also reminds that children, pregnant women, and the elderly are high-risk groups and need to be extra vigilant about temperature changes and bodily responses.
(This article referenced a report from “USA Today”)