Hennepin, IL Climate

Climate Insight: Hennepin, IL

The NOAA 1991–2020 climate normals describe Hennepin, Illinois as a location with an annual average temperature of 51°F, ranging from a mean daily high of 61°F to a mean daily low of 42°F. July is typically the warmest month of the year, while January is the coldest. These thirty-year averages, computed from station USC00114012, smooth out year-to-year variability and give a baseline expectation for typical conditions in any given month.

Precipitation patterns matter as much as temperature for anyone planning to live, garden, or travel here. Hennepin receives roughly 38.6 inches of precipitation each year, predominantly as rainfall. Growing-season length varies with elevation and microclimate, with the last spring freeze near April 18 and the first fall freeze near October 22. For energy use, 5,869 heating degree days and 946 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Hennepin scores 67/100 (Good), 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 January-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.