By total land area, Davis County is the smallest county in Utah. Its total area is 634 square miles (304 sq mi of land; 329 sq mi of water). Davis County is part of the Wasatch Front; to its north is Weber County, to its south is Salt Lake County, to the west is the Great Salt Lake and then Box Elder and Toole County, and to the east is the Wasatch Mountain Range and Morgan County.The average elevation in Davis County is approximately 4,200 feet, with the highest peak in the county of Thurston Peak at 9,707 feet.
Davis County is considered by scientists to be in a cold semi-arid climate, which means the climate can feature warm to hot summers and cold, sometimes very cold winters, as well as major temperature swings between day and night by as much as 55 degrees Fahrenheit.
The coldest temperatures in Davis County occur in January with an average low of 20°F; whereas the hottest temperatures occur in July with an average high of 89°F.
Annual precipitation levels average between 18 and 25 inches, with the month of May being the highest with an average of 2.7 inches and the month of July being the lowest with only 0.98 inches. It must be noted that due to Davis County’s bordering relationship with the Great Salt Lake, an occurrence called “Lake-Effect Snow” can produce above average snowfalls because cold winds from the west move across the long expanse of the Great Salt Lake’s warmer water, providing energy and picking up water vapor which freezes and is deposited onto the relatively narrow section of Davis County that is sandwiched between the Great Salt Lake to the west and the Wasatch Mountain Range to the east. This can lead to snow during the winter on the valley floor of Davis County of roughly 60 inches and on the high bench areas up to 90 inches.