Lewistown, MT Climate

Climate Insight: Lewistown, MT

The NOAA 1991–2020 climate normals describe Lewistown, Montana as a location with an annual average temperature of 41°F, ranging from a mean daily high of 54°F to a mean daily low of 27°F. July is typically the warmest month of the year, while February is the coldest. These thirty-year averages, computed from 4 weather stations, smooth out year-to-year variability and give a baseline expectation for typical conditions in any given month.

Lewistown averages 16.8 inches of precipitation a year, with seasonal snowfall possible, and that matters as much to daily life here as temperature does. The frost-free season averages 81 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near June 15 and the first fall freeze near September 4. As for energy demand, 8,917 heating degree days and 46 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Lewistown scores 44/100 (Moderate), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. Use the monthly tables above to plan around specific windows, shoulder seasons for mild highs and lows, peak summer for July-driven heat, or deep winter for February-driven cold. All figures here are thirty-year averages: any single year may run warmer, wetter, drier, or cooler than the normal, so treat them as planning guidance rather than forecasts.