Climate
Southeast Utah is part of the Colorado Plateau, a "high desert" region that experiences wide temperature fluctuations, sometimes over 40 °F 22 °C in a single day. The temperate and most popular seasons are spring April through May and fall mid-September through October, when daytime highs average 60 to 80°F 15 to 27°C and lows average 30 to 50°F -1 to +10°C.
Summer temperatures often exceed 100°F 38°C, making strenuous exercise difficult. Late summer monsoon season brings violent storm cells which often cause flash floods.
Winters are cold, with highs averaging 30 to 50°F -1°C to +10°C, and lows averaging 0 to 20°F -18 to -7°C. Though large snowfalls are uncommon except in nearby mountains, even small amounts of snow or ice can make local trails and roads impassable.
Local weather conditions and forecasts are available by phone at 801 524-5133.
Understand
Arches National Park preserves over 2,000 natural sandstone arches. This area contains the largest concentration of arches found any where in the world, including the world-famous Delicate Arch as seen on the Utah state license plate, in addition to a variety of unique geological resources and formations. In some areas, faulting has exposed millions of years of geologic history.The extraordinary features of the park, including balanced rocks, fins and pinnacles, are highlighted by a striking environment of contrasting colors, landforms and textures.
History
Throughout the park, rock layers reveal millions of years of deposition, erosion and other geologic events. These layers continue to shape life in Arches today, as their erosion influences elemental features like soil chemistry and where water flows when it rains. Arches is in a "high desert," with elevations ranging from 4,085 to 5,653 feet above sea level.
In 1923 Alexander Ringhoffer, a prospector, wrote the Rio Grande Western Railroad in an effort to publicize the area and gain support for creating a national park. Ringhoffer led railroad executives interested in attracting more rail passengers into the formations; they were impressed, and the campaign began. The government sent research teams to investigate and gather evidence. In 1929, President Herbert Hoover signed the legislation creating Arches National Monument, to protect the arches, spires, balanced rocks, and other sandstone formations. In 1971 Congress changed the status of Arches to a National Park, recognizing over 10,000 years of cultural history that flourished in this now famous landscape of sandstone arches and canyons.
Landscape
To many, the most outstanding natural features of Arches are the park's geologic formations. Over 2,000 catalogued arches range in size from a three-foot opening the minimum considered to be an arch, to Landscape Arch which measures 306 feet from base to base. Towering spires, fins and balanced rocks complement the arches, creating a remarkable assortment of landforms in a relatively small area.
Two unusual natural features common in Arches intrigue both scientists and visitors: cryptobiotic soil and potholes. Cryptobiotic soil is a living groundcover that forms the foundation of high desert plant life.
Potholes are naturally occurring basins or pools in sandstone that collect rainwater and wind-blown sediment. These potholes harbor organisms that are able to survive long periods of dehydration, and also serve as a breeding ground for many desert amphibians and insects. Both of these communities are very vulnerable to human impacts.