are maintained by the U.S. Army Corps of Engineers. According to the U.S. Census Bureau, the city has a total area of , of which is land and is water. Downtown Lewiston, at elevations between and , is only slightly higher in elevation than the river, about , which was lower prior to the completion of the Lower Granite Dam. Away from downtown the terrain gains elevation quickly, as the steep riverbank highway of U.S. 95 north of Lewiston ascends to . The lowest point in the state of Idaho is located on the Snake River in Lewiston, where it meets the Clearwater and flows west into Washington. The populated areas in Idaho with the lowest elevations are along (or near) the Clearwater River, from Lowell at to Lewiston. The Orchards The heavily residential southern half of the city is referred to as "The Orchards". This area is much higher in elevation than downtown, at about , and is named for the fruit orchards that previously covered the area. Formerly unincorporated, it was annexed which nearly doubled the city's population and doubled the area of the city. There is little sign of any orchards today, although there is a wide proliferation of fruit trees in the backyards of many residences in this area of town. The Lewiston-Nez Perce County Airport is located on the western edge of the Orchards plateau at above sea level, with Bryden Canyon Road providing westbound access via the Southway Bridge into Clarkston. Climate Lewiston experiences a semi-arid climate (Köppen BSk) with occasionally cold, but short, winters, mostly influenced by mild Pacific air, and hot, dry summers. The monthly daily average temperature ranges from in December to in July; the temperature reaches on 7.7 afternoons, on 42 afternoons, and does not rise above freezing on 14 afternoons annually. Precipitation averages annually, including an average seasonal snowfall of . At 195 days, the growing season is relatively long, with the average window for freezing temperatures being October 23 thru April 10. The plant hardiness zone are 7 and 8 with temperatures below being rare. Extreme temperatures range from on December 13, 1919 to on July 27, 1939. Tornadoes are very rare with only three tornadoes being reported in Nez Perce County since 1950, and the only significant tornado was an F2 in Lapwai on May 8, 1962. Demographics 2010 census As of the census of 2010, there