Forecasters warn a coast-to-coast heat surge could push parts of the U.S. into the 100s this month

An expansive early-summer warmup is expected to spread across nearly the entire contiguous United States, with forecasts calling for highs in the 80s and 90s and, in some places, above 100 degrees.

Forecasters say a sprawling zone of high pressure could hold that heat over much of the country until at least mid-June, creating dangerous conditions in many areas.

What's happening?

From June 11-17, outlook maps point to warmer-than-normal conditions across all 48 contiguous states, USA Today reported.

Ben Noll, a meteorologist at The Washington Post, said "a period of record-breaking heat and increasing humidity is possible across much of the country into the middle part of the month."

A strong ridge in the atmosphere is behind the pattern. In this kind of high-pressure setup, sinking air compresses and warms, which often means sunnier skies, less rainfall, and hotter conditions at the ground.

As NOAA explained, "Typically a summertime occurrence, ridges are responsible for major heat waves."

Some of the first notable impacts may arrive along the East Coast.

NOAA's Weather Prediction Center said, "Warm low temperatures over much of the Mid-Atlantic could lead to moderate-to-major heat risk impacts for those without adequate cooling and hydration."

Meteorologist Thomas Collow also noted that while some cooler weather could briefly move through parts of the West, "temperatures are forecast to quickly rebound" there, with more persistent warmth likely across the western U.S. into late June.

Why does it matter?

Extreme heat is one of the deadliest forms of severe weather because it puts stress on the body, worsens dehydration, and can quickly become dangerous for children, older adults, pregnant people, outdoor workers, and anyone without dependable cooling.

Warm overnight temperatures are especially concerning because they make it harder for the body to recover after a hot day.

Beyond the direct health threats, worsening extreme weather can strain hospitals, infrastructure, and household budgets. Heat waves can interrupt work, threaten crops and livestock, raise wildfire risk, and drive up energy use as families try to stay cool indoors.

Those effects can ripple through community safety and economic stability, especially in drought-stricken regions.

"Greater than half the lower 48 is also experiencing moderate drought conditions, helping to further increase temperatures over drier regions," Collow noted, per USA Today.

That mix of heat and dryness can quickly intensify local impacts.

What can I do?

Prepare before the hottest days arrive. Check your local forecast for heat alerts, the UV index, and the feels-like temperature, and make sure you have access to water, shade, and air conditioning.

If you need to spend time outside, wear loose, lightweight, light-colored clothing and reapply sunscreen regularly. Never leave children or pets in a parked car, even briefly, since interior temperatures can become deadly very quickly.

Check in on neighbors, relatives, and friends who may be especially vulnerable to the heat, particularly older adults or people without reliable cooling. Even nighttime temperatures can become dangerous during extended warm spells.

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