US Feels the Heat

More than 110 million people were under heat advisories yesterday as a far-reaching heat wave settled across the southern US stretching from California to Florida. Triple-digit temperatures are expected to persist through the weekend in many locations, particularly in the Southwest.

The culprit is a heat dome—a high-pressure system trapped under a northward bulge in the jet stream—exacerbated by an El Niño weather pattern. Hot spots include Palm Springs, California, which is projected to reach 119 degrees today; Phoenix, Arizona, is on track to break its record of consecutive nights above 90 degrees; and Marathon Key, Florida, saw the heat index hit 118 degrees. California's Death Valley, one of the hottest places on Earth (see 101), is expected to pass 130 degrees this weekend, nearing its all-time high of 134 degrees.

The heat comes on the heels of what NASA measurements say was the hottest month of June on record, with global temperatures 1.9 degrees above the historical average.