The Great Basin is effectively cut off from the westerly flow of Pacific moisture. Orographic uplift of crossing air masses by the Sierra and the Cascades provides cooling and precipitates much of the moisture out. The result is a BSk (Dry Steppe cold) climate classification for most of the Basin in the Koeppen system. The climate is typical of middle latitude, semi-arid lands where evaporation potential exceeds precipitation throughout the year. There is no water surplus or stream originating in such a climate, and mean annual temperatures are under 64.4[[ring]]F (18[[ring]]C). Oases occur where highlands generate surface streams or springs. By the time air masses reach the Basin's eastern edge they get another lift, creating extra moisture and highland climates that support Utah's population corridor below. High-level, low-pressure systems affecting Utah weather at the precipitation maximums in spring and fall are often referred to as "Great Basin" or "Nevada" lows.
The vegetation response to the Great Basin's climate, soils, and topography can be generalized in a look at its life zones. Plants range from Upper Sonoran sagebrush-grasslands through Transition (Foothill) sagebrush, juniper, and piñon to Canadian (Montane) pockets of aspen-fir on prime mountain range locations. Soils grade upslope from Aridisols through Mollisols with occasional young Entisols appearing on the fans, floodplains, and valley bottoms. Interior basins are commonly around 4,000 to 5,000 feet above sea level and ranges as high as 10,000 (and occasionally 12,000 feet) in elevation.