Salt Lake City's Climate¹

Salt Lake City is located in the Salt Lake Valley, a northern Utah valley surrounded by mountains on three sides with the Great Salt Lake to the northwest.  The Wasatch Mountains five miles (eight kilometers) to the east have peaks to nearly 12,000 feet (3,660 meters) above sea level.  Their orographic effects cause more precipitation in the eastern part of the city than over the western part.  The Oquirrh Mountains seven to eight miles (eleven to thirteen kilometers) to the southwest of the city have several peaks above 10,000 feet (3,050 meters).  The Traverse Mountain Range at the south end of the Salt Lake Valley rises to above 6,000 feet (1,830 meters).  These mountain ranges shelter the valley from storms from the southwest in the winter, but are instrumental in developing thunderstorms which can drift over the valley in the summer.

Besides the mountain ranges, the most influential natural condition affecting the climate of Salt Lake City is the Great Salt Lake, about 10 miles (12 kilometers) northwest of the city.  This large inland body of water, which never freezes due to its high salt content, moderates the temperatures of cold winter winds blowing from the northwest and helps drive a lake/valley wind system.  The warmer lake water during the winter and spring also contributes to increased precipitation in the valley downwind from the lake—the “lake effect”.  The combination of the Great Salt Lake and the Wasatch Mountains often enhances storm precipitation in the valley.

Salt Lake City normally has a semi-arid continental climate with four well-defined seasons.  Summers are characterized by hot, dry weather, but the high temperatures during this season are usually not oppressive, since the relative humidity is generally low and the nights usually cool.  July is the hottest month with an average maximum reading in the low 90s F. (30s C.).  The highest temperature on record is 107º F. (42° C.).  January is the coldest month with an average daily minimum around 20º F. (-7° C.).  The lowest recorded temperature is -30º F. (-34° C.) 

The mean diurnal temperature range is about 30 degrees F. in the summer and 18 degrees F. during the winter.  Temperatures above 102° F. (39° C.) in the summer or colder than -10° F. (-23° C.) in the winter are likely to occur one season out of four.  

Winters are cold, but usually not severe.  Mountains to the north and east act as a barrier to frequent invasions of cold continental air.  The average snowfall is 58 inches (1,473 millimeters) at the airport but much higher amounts fall in higher bench locations.  The average seasonal snowfall ranges between 40 and 50 inches (1,016 and 1,270 mm) in the lower valleys and average duration of continuous snow coverage at the Salt Lake City International Airport is 29 days.  Occasionally, the snow cover is considerably more than 1 foot (300 mm) deep. Heavy fog can develop under temperature inversions in the winter and persist for several days.  

Precipitation, generally light during the summer and early fall, is heavy in the spring when storms from the Pacific Ocean are moving through the area more frequently than at any other season of the year.  Owing to the modifying influence of the Wasatch and Oquirrh Mountain ranges, the annual average precipitation varies from about 16 inches (406 mm) at the airport to more than 30 inches (762 mm) in higher elevations.  Precipitation is relatively light during summer and early fall and reaches a maximum in spring.  The wettest month is usually April, when most parts of the valley receive almost two inches (610 mm) of moisture.  July is usually the driest month.  About one-third of the annual precipitation falls as snow, most of which occurs between December and March.

Winds are usually light—the mean speed is 8.8 mph (14.2 kph).  Occasional high winds have occurred in every month of the year.  Strong winds are associated either with easterly winds blowing out of the canyons or with local severe thunderstorms; however, the canyon winds do not usually extend more than five miles (eight kilometers) from the mouth of the canyons.  The overall prevailing wind direction is from the south-southeast.

The growing season is over five months in length.  Yard and garden foliage generally are making good growth by mid-April.  The last freezing temperature in the spring averages late April and the first freeze of the fall is usually in mid-October.  

¹National Oceanic and Atmospheric Administration.  Local Climatological Data, Annual Summary with Comparative Data: Salt Lake City, Utah.  Asheville, N.C.: National Climatic Data Center, 1991.