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Lake Forest city, Illinois

Official LSAD Designation: Lake Forest city • Census GEOID: 1741105 • Lake County

Climate Normals & Weather Observations

30-year climate normals (1991–2020) and weather observations for Lake Forest city.

Reference Weather Station: CHICAGO BOTANIC GARDEN, IL US (ID: USC00111497) • Located 7.6 miles from community center • Elevation: 192.0 m
Month Average High (°F) Average Low (°F) Mean Temp (°F) Precipitation (in)
January 32.3° 16.3° 24.3° 2.10"
February 36.0° 19.1° 27.5° 1.98"
March 45.8° 28.2° 37.0° 2.26"
April 56.8° 37.6° 47.2° 4.00"
May 68.2° 47.6° 57.9° 4.84"
June 78.4° 57.3° 67.9° 4.31"
July 83.5° 63.4° 73.4° 3.74"
August 82.0° 62.3° 72.2° 4.16"
September 75.2° 54.7° 64.9° 3.56"
October 62.8° 42.7° 52.7° 3.59"
November 49.0° 32.5° 40.8° 2.63"
December 37.5° 22.3° 29.9° 2.34"

Annual Temperature History

2010–2025, completed calendar years only.

NOAA station CHICAGO BOTANIC GARDEN, IL US (ID: USC00111497) • 7.6 miles from community center .

This is the same reference station used for monthly normals.

Annual mean Annual mean of daily highs Annual mean of daily lows
Annual temperature history at CHICAGO BOTANIC GARDEN, IL US Year is the horizontal axis. Annual mean temperature in degrees Fahrenheit is the vertical axis. Dots show recorded years; lines connect consecutive available years only. Missing years are gaps, with no interpolation. Optional dashed lines show annual mean of daily highs and lows. Exact values appear in the data table below. 34.0 42.0 50.0 58.0 66.0 2010 2014 2018 2021 2025 Year Annual mean temperature (°F) 2010: Annual mean 51.0°F 2011: Annual mean 50.3°F 2012: Annual mean 53.3°F 2013: Annual mean 48.1°F 2014: Annual mean 46.1°F 2015: Annual mean 49.6°F 2016: Annual mean 51.7°F 2017: Annual mean 50.9°F 2018: Annual mean 49.2°F 2010: Annual mean of daily highs 60.6°F 2011: Annual mean of daily highs 59.2°F 2012: Annual mean of daily highs 63.1°F 2013: Annual mean of daily highs 57.5°F 2014: Annual mean of daily highs 55.4°F 2015: Annual mean of daily highs 58.7°F 2016: Annual mean of daily highs 60.6°F 2017: Annual mean of daily highs 60.1°F 2018: Annual mean of daily highs 57.9°F 2010: Annual mean of daily lows 41.5°F 2011: Annual mean of daily lows 41.5°F 2012: Annual mean of daily lows 43.6°F 2013: Annual mean of daily lows 38.8°F 2014: Annual mean of daily lows 37.0°F 2015: Annual mean of daily lows 40.5°F 2016: Annual mean of daily lows 42.8°F 2017: Annual mean of daily lows 41.8°F 2018: Annual mean of daily lows 40.5°F

Source: NOAA NCEI Global Summary of the Year.

Annual temperature data table (°F)
Annual station temperatures, 2010–2025. Unavailable means no reported value.
Year Annual mean (°F) Annual mean of daily highs (°F) Annual mean of daily lows (°F)
2010 51.0 60.6 41.5
2011 50.3 59.2 41.5
2012 53.3 63.1 43.6
2013 48.1 57.5 38.8
2014 46.1 55.4 37.0
2015 49.6 58.7 40.5
2016 51.7 60.6 42.8
2017 50.9 60.1 41.8
2018 49.2 57.9 40.5
2019 Unavailable Unavailable Unavailable
2020 Unavailable Unavailable Unavailable
2021 Unavailable Unavailable Unavailable
2022 Unavailable Unavailable Unavailable
2023 Unavailable Unavailable Unavailable
2024 Unavailable Unavailable Unavailable
2025 Unavailable Unavailable Unavailable
Source: NOAA NCEI 1991–2020 U.S. Climate Normals, National Weather Service.