Environmental Factors

Thunderstorms over the Painted Desert.

Photo by T.Scott Williams/PFMA

The clarity of the high, dry air over the Painted Desert region is only interrupted by weather shifts and environmental factors. Wind plays a large role in shaping the terrain but does not often decrease visibility except in the spring and early summer. With an annual rainfall of ~10 inches (~25 cm), moisture seldom interrupts the majestic vistas.

When the rains do come, the conditions can be dramatic. Thunderstorms are most common during the monsoon season, July to September. Winters can bring cold temperatures, wind, ice, and snow. Spring is best known for its wind and dust storms. Fall is sublime, with temperate days and cool nights.

While automobile traffic and the passage of trains on the Santa Fe line can be heard from the road, the backcountry is still a refuge of profound silence. This relative isolation has also helped to preserve the night skies and the air quality within the park.

Petrified Forest is one of the national parks that has Class I air. Class I National Park Service areas have the highest level of air quality protection under the law. These areas are defined as national parks larger than 6,000 acres or wilderness areas over 5,000 acres that were in existence when the Clean Air Act was amended in 1977. To learn about Class I air in the national parks, visit Petrified Forest National Park Air Quality Information and the Class I Areas.