From high heat in the middle of summer to the potential of zero degrees Fahrenheit (-17.8 degrees Celcius) some winter nights, Canyonlands offers a wide range of temperatures and seasons for park goers.

A winter view at Green River Overlook, Canyonlands National Park / Rebecca Latson
Southeast Utah is part of the Colorado Plateau, a "high desert" region that experiences wide temperature fluctuations, sometimes over 40 degrees (4 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 (15.5 to 26.6 C) and lows average 30 to 50 F (-1 to 10 C).
Summer temperatures often exceed 100 F (37.8 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 to 10 C), and lows averaging 0 to 20 F (-17.8 to -6.7 C). Though large snowfalls are uncommon (except in nearby mountains), even small amounts of snow or ice can make local trails and roads impassable.