Friday marks the official start of summer, accompanied by the first major heat wave of the season in the United States. The National Weather Service (NWS) has warned that many regions will experience heat index levels exceeding 100°F, driven by a combination of high temperatures and intense humidity.
In the Northeast, cities like Philadelphia have issued red alerts to safeguard vulnerable populations, including homeless individuals, by moving them to indoor facilities. These alerts are triggered when the forecasted heat index remains above 95°F for three or more consecutive days.
Farther west, cities such as St. Louis could face a prolonged period of extreme heat, with perceived temperatures reaching up to 108°F. In Wisconsin, heat indexes may rise between 100°F and 105°F. Experts note that a relatively mild spring has left many unaccustomed to such extreme summer conditions.
The heat index measures how hot it feels by factoring in both temperature and humidity. This wave of extreme heat is expected to spread from the Great Plains through the Midwest, Great Lakes, and into the East Coast. Relief from the high temperatures is unlikely until late next week.
The National Weather Service advises residents to take precautions early. Recommended measures include staying in shaded or air-conditioned spaces, drinking water regularly—even when not thirsty—and never leaving anyone, including pets, in enclosed vehicles. Populations at highest risk include children, the elderly, pregnant individuals, and those with chronic health conditions.
Heat waves in the U.S. have become more frequent and prolonged in recent decades. Since the 1980s, the average number of annual heat waves has doubled, and the length of the heat wave season has increased from roughly 40 to 70 days.
The summer of 2024 has been recorded as the hottest since global temperature tracking began in the 1800s, surpassing the previous record set in 2023. These extreme weather events highlight the ongoing environmental challenges associated with global climate changes, which impact not only human health but also ecosystems and natural landscapes.
