Oak Forest, IL climate
Oak Forest has chilly winters and pleasant summers. A typical July afternoon reaches 84°, a January night drops to 17°, and about 28 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Oak Forest feels like
Winter
Spring
Summer
Fall
Oak Forest weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 17° | 2.2" | 10.2" | 11 | 18 | 15° – 36° |
| February | 36° | 20° | 1.9" | 7.5" | 9 | 13 | 16° – 39° |
| March | 48° | 29° | 2.5" | 4.9" | 10 | 5 | 30° – 53° |
| April | 60° | 39° | 3.9" | 0.5" | 12 | 0 | 41° – 56° |
| May | 71° | 49° | 4.5" | 0 | 13 | 0 | 54° – 67° |
| June | 81° | 59° | 4.4" | 0 | 10 | 0 | 66° – 74° |
| July | 84° | 64° | 4.1" | 0 | 9 | 0 | 69° – 80° |
| August | 82° | 62° | 4.1" | 0 | 9 | 0 | 67° – 78° |
| September | 76° | 55° | 3.4" | 0 | 8 | 0 | 59° – 69° |
| October | 63° | 43° | 3.5" | 0.2" | 11 | 0 | 49° – 59° |
| November | 49° | 32° | 2.7" | 0.9" | 10 | 1 | 33° – 49° |
| December | 37° | 23° | 2.2" | 4.0" | 11 | 9 | 16° – 39° |
| Year | 60° | 41° | 39.4" | 28.2" | 124 | 46 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Oak Forest
Oak Forest gets 39 inches of rain and melted snow a year. May is the wettest month and February the driest. Rain or snow falls on about 124 days a year. Snow covers the ground about 46 days of the year.
About 179 frost-free days a year
In half of years the last 32° night comes by April 23 and the first one by October 20. That leaves about 179 frost-free days for gardens, longer than 51% of U.S. towns.
Heating and cooling a home in Oak Forest
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Oak Forest, 88% of that work is heating and 12% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Oak Forest and its neighbors
Oak Forest borders 4 towns with climate data. January nights across them vary by 0.8°. Orland Park has the coldest January nights (17°) and Midlothian the hottest July afternoons (84°). Oak Forest’s January low is 17° and its July high 84°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Oak Forest compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Oak Forest averaged 1.2° warmer than the 1900s. The biggest change is in December (+2.5°). The shift is larger than in 51% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Oak Forest’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. December swings the most: between 1991 and 2020 its average temperature ranged from 16° to 39°. June is the most reliable, staying within 9°.
Common questions about Oak Forest’s climate
What is the coldest month in Oak Forest?
January, with a typical high of 32° and a low of 17°.
What is the hottest month in Oak Forest?
July, with a typical high of 84° and a low of 64°. About 16 days a year reach 90°.
How much snow does Oak Forest get?
About 28 inches in a normal winter, most of it in January.
When is the first frost in Oak Forest?
In half of years the first 32° night comes by October 20, and the last spring frost by April 23.
What is the rainiest month in Oak Forest?
May, with 4.5 inches of rain and melted snow. The year totals 39 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Oak Forest itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Park Forest, IL (9 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.