Heat Dome: Scorching US Heatwave Hits 70 Million

About 70 million people across the southern and central United States are facing excessive heat advisories as the third major heat dome event in a month settles over the region. The system, which gathered strength over the weekend, spans from the Gulf of Mexico coast through the Great Plains and into the Midwest.

Temperatures are expected to range from 95°F to 105°F (35–40°C), with some areas of the southwestern desert potentially reaching 120°F (48°C). The heat advisory, issued through Monday, warns that feels-like temperatures will soar at or above 105°F. After the advisory expires, humidity is expected to drop, with feels-like temperatures returning to the 90s on Tuesday.

What Is a Heat Dome?

A heat dome occurs when a high-pressure atmospheric system acts as a lid, trapping heat over a region for days or even weeks. This phenomenon is not new to American summers, but the regularity and severity of such events are worsening due to the human-caused climate crisis. The release of heat-trapping gases from burning fossil fuels has pushed global temperatures beyond anything previously experienced during human civilization.

Earlier this summer, a similar heat dome event in early July caused the cancellation of Independence Day events in the eastern United States. The current system marks the third such event in a month, underscoring a troubling pattern.

Forecast and Safety

The elevated heat is expected to linger into the coming week, held in place by the heat dome. Residents in affected areas are advised to stay indoors, drink plenty of water, and listen to their bodies. The heat advisory remains active through Monday, after which a slight cooldown is expected, primarily due to a drop in humidity rather than a significant temperature change.

For more on how to stay safe during extreme heat, see our heat safety guide.

Broader Climate Context

While heatwaves are a natural part of summer, the increasing frequency and intensity of heat dome events are directly linked to climate change. The current event is part of a larger trend that has seen record-breaking temperatures across the globe. For a deeper dive into the causes and impacts of these phenomena, read our analysis on US heat dome causes, impacts, and climate links.

As the planet continues to warm, understanding the mechanics of heat domes and preparing for their effects becomes ever more critical. The coming days will test the resilience of communities from the Gulf to the Great Plains, but the forecast offers a glimmer of relief by midweek.