Summary (tl;dr)

A significant "heat dome" event is currently gripping vast portions of the central, western, and southern United States, bringing dangerously high temperatures and extreme humidity to tens of millions of people. This marks the third major heat dome to impact the U.S. this summer, intensifying concerns about climate change and its effect on extreme weather patterns.

Essential Background

A heat dome is a weather phenomenon where a persistent ridge of high pressure traps a mass of hot air beneath it, much like a lid on a pot. This high-pressure system pushes warm air downwards, compressing it and causing temperatures to soar. The trapped air is prevented from rising, and clouds are unable to form, allowing more solar radiation to hit the ground, further intensifying the heat. This leads to prolonged periods of extreme heat that can last for days or even weeks. Scientists link the increasing frequency and severity of these events to human-driven climate change.

The Full Story

As of late July 2026, a powerful heat dome is expanding across the central United States, creating hazardous conditions for an estimated 70 million people under heat advisories. Temperatures are forecast to exceed 100°F (37.8°C) from Dallas, Texas, north to North Dakota, with some areas experiencing temperatures 10°F to 15°F (5.6°C to 8.3°C) above normal. High humidity is making the "feels like" temperatures even more oppressive. This extreme heat is predicted to remain largely stationary through the week, allowing heat stress to build as overnight low temperatures offer little relief. This follows earlier heat dome events in early and mid-July, which brought record-breaking temperatures to areas of the East, Southwest, and Great Plains.

Why It Matters

The current heat dome poses significant health risks, particularly for vulnerable populations such as the elderly, young children, and individuals with pre-existing health conditions, as extreme heat can worsen heart, lung, and kidney diseases. The prolonged high temperatures and humidity can lead to heatstroke, heat exhaustion, and increased hospitalizations. Beyond human health, the sustained heat puts a severe strain on infrastructure, including power grids that face increased demand for air conditioning, and contributes to drought conditions, elevating the risk of wildfires, especially in the Plains and Midwest. Experts emphasize that these more frequent and intense heat waves are consistent with projections made in the 1990s regarding the impacts of climate change.

Geographic Location

• Central United States (widespread dangerous heat and heat advisories affecting 70 million people)
• Dallas, Dallas County, Texas, United States (temperatures above 100°F)
• North Dakota, United States (temperatures above 100°F)
• Denver, Denver County, Colorado, United States (potential record-breaking temperatures, cooling centers opened)
• Western Nebraska, United States (extreme heat warning, temperatures up to 108°F)
• Billings, Yellowstone County, Montana, United States (record high of 111°F on July 13)
• Wyoming, United States (record-breaking temperatures on July 12)
• Las Vegas, Clark County, Nevada, United States (expected extreme heat)
• Salt Lake City, Salt Lake County, Utah, United States (all-time high of 109°F on July 12)
• Phoenix, Maricopa County, Arizona, United States (reached 113°F on July 6-8)
• Minneapolis, Hennepin County, Minnesota, United States (could set new record highs)
• Indianapolis, Marion County, Indiana, United States (could set new record highs, cooling stations at Indianapolis Motor Speedway)
• Chicago, Cook County, Illinois, United States (could set new record highs)
• Omaha, Douglas County, Nebraska, United States (could set new record highs)
• Louisiana, United States (dangerous humid heat forecast)
• Florida, United States (dangerous humid heat forecast)