Knoxville, IL Climate

Climate Insight: Knoxville, IL

In Knoxville, Illinois, the NOAA 1991–2020 climate normals put the annual average temperature at 50°F, ranging from a mean daily high of 60°F to a mean daily low of 41°F. July is typically the warmest month of the year, while January is the coldest. As thirty-year averages computed from station USC00114780, these numbers smooth out year-to-year noise into a working baseline for a typical month.

Knoxville averages 40.5 inches of precipitation a year, with 25.4 inches typically falling as snow, and that matters as much to daily life here as temperature does. The frost-free season averages 182 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 21 and the first fall freeze near October 20. As for energy demand, 6,191 heating degree days and 899 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Knoxville scores 63/100 (Good), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. The monthly tables above are the practical planning tool: mild highs and lows land in the shoulder seasons, July-driven heat peaks in summer, and January-driven cold sets in over deep winter. These are thirty-year averages, not a forecast - any single year can run warmer, wetter, drier, or cooler than the normal.