Chicago Northerly IS, IL Climate

Climate Insight: Chicago Northerly IS, IL

Chicago Northerly IS, Illinois runs an annual average of 51°F, ranging from a mean daily high of 57°F to a mean daily low of 44°F, per NOAA's 1991–2020 climate normals. July is typically the warmest month of the year, while January is the coldest. Drawn from station USC00111550, these thirty-year averages smooth out year-to-year swings into a baseline for what a typical month looks like here.

Rainfall (and snow, where it falls) shapes day-to-day life here as much as temperature does. Chicago Northerly IS sees about an uncharted amount of precipitation a year, predominantly as rainfall. The frost-free season averages 209 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 10 and the first fall freeze near November 5. On the energy side, 6,018 heating degree days and 862 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Chicago Northerly IS scores 53/100 (Moderate), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. For planning purposes, look to the monthly tables above: shoulder seasons bring the mildest highs and lows, summer brings July-driven heat, and deep winter brings January-driven cold. Treat every figure here as a thirty-year average rather than a forecast - individual years routinely run warmer, cooler, wetter, or drier than the normal.