Newberry Volcano has an extremely dry climate due to its location in the rain shadow of the Cascade Range. Climate data for the Newberry National Volcanic Monument are collected at the Lava Butte cinder cone, which had an average annual precipitation of from 2002 to 2012. Summer temperatures average from , dipping to average minimum and maximum temperatures of during the winter season. Spring has average temperatures of , while fall temperatures average . Each year, total precipitation consisting of winter snow and summer rain varies from in the highest parts of the region, and surface runoff rarely occurs even during heavy rain showers. Only one stream appears on Newberry's entire surface, and it remains unclear whether the volcano has ever been able to support glaciers on its slopes, since the mountain lacks cirques (amphitheater-like valleys formed by glacial erosion) or evidence of contact between lava and ice. However, displaced glacial erratics have been found far from their native areas, moraine sediment has been deposited on the eastern and northeastern slopes of the volcano, and the mountain's various cone features have boat shapes that indicate glacial alteration. The precise history of glaciers on the volcano is debated, but dry channels and dry waterfalls on the eastern and western slopes are evidence that the volcano once held water.