Death Valley National Park

Death Valley National Park


Death Valley is the hottest and driest place in the United States. A temperature of 134°F, the second-highest ever recorded in the world, was noted in 1913 (only Libya has ever beaten that record with a recorded temperature of 136°F in 1922). The sweltering valley receives less than two inches of rain per year. 

Why is Death Valley so dry? 

Winter storms moving inland from the Pacific Ocean must pass over a number of mountain ranges as they travel east. As the clouds rise with the mountains, they cool and the moisture falls as rain or snow on the western side of the mountains. By the time the clouds reach the mountains' east side, most of the moisture has already been precipitated, leaving a dry "rainshadow." Four major mountain ranges lie between Death Valley and the ocean, each one adding to the intensity of the rainshadow effect. In total, rainfall averages less than two inches per year. During some years, there is no rain at all.

Why is Death Valley so hot? 

The depth and shape of Death Valley contributes to the hot summer temperatures. The valley is a long, narrow basin 282 feet below sea level, yet walled by high, steep mountain ranges. The clear, dry air and sparse plant life cover allow sunlight to continuously heat the desert surface. Heat radiates back from the rocks and soil and becomes trapped in the valley's depths. Summer nights provide little relief. Often, overnight lows may only dip to 90°F. Heated air rises, yet it is trapped by the high valley walls and is cooled and recycled back down to the valley floor. Those pockets of descending air are only slightly cooler than the surrounding hot air. As they descend, they are compressed and heated even more by low elevation air pressure. These moving masses of super-heated air blow through the valley—creating the extremely high temperatures. 

Weather Facts

• The ground temperature can be 80°F hotter than the air temperature. A ground temperature of 201°F was once measured in Death Valley. Ground temperature on the valley floor is about 40 percent higher than the surrounding air temperature. 

• The lowest temperature ever recorded on the valley floor was 15°F in 1913.

• Higher elevations are cooler than the low valley. Temperatures drop 3° to 5°F with every 1,000 vertical feet.

• In 2001, Death Valley recorded 154 days in a row with temperatures of 100°F or above—the greatest number of consecutive days with three-digit temperatures!

• On average, Death Valley is the hottest place in the world. July is characteristically the hottest month with an average temperature of 116°F.