Southeast Utah is part of the Colorado Plateau, a "high desert" region that experiences wide temperature fluctuations -- sometimes over 40 degrees in a single day. Whatever the season, visitors should come prepared for a range of weather conditions. Spring (April-May) and fall (September-October) are the temperate (and most popular) seasons, when daytime highs average 60-80°F and lows average 30-50°F. Summer temperatures often exceed 100°F, making strenuous exercise difficult. Late summer monsoon season brings violent storm cells which often cause flash floods.
Winters are cold, with highs averaging 30-50°F and lows averaging 0-20°F. Though large snowfalls are uncommon (except in nearby mountains), even small amounts of snow or ice can make local trails and roads impassable, such as the unpaved roads leading to outlier archeological sites.