Fairfield Average Temperature by Month

This page shows the average temperature in each month of the year in Fairfield, Illinois. It is based on NOAA data for the years 1991–2020.
What's the Hottest Month in Fairfield?
In Fairfield, Illinois, the warmest month is July, with an average daily high temperature of 88.5 °F and an average low of 66.2 °F.
What's the Coldest Month in Fairfield?
In Fairfield, Illinois, the coolest month is January, with an average daily high temperature of 40.0 °F and an average low of 23.2 °F.
Month Avg. High Avg. Low
January 40.0 °F 23.2 °F
February 45.5 °F 26.7 °F
March 55.9 °F 34.9 °F
April 67.9 °F 45.0 °F
May 77.0 °F 54.6 °F
June 85.8 °F 62.8 °F
July 88.5 °F 66.2 °F
August 87.7 °F 64.3 °F
September 81.5 °F 56.5 °F
October 69.5 °F 45.5 °F
November 55.1 °F 35.1 °F
December 43.9 °F 27.5 °F
Year 66.6 °F 45.2 °F
Weather Station Details
Years Station Coordinates
1895–2024 Fairfield Radio WFIW location
© H Brothers Inc, 2021–2024
Contact us | Privacy policy