Oak Lawn, Illinois Weather
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Climate of Oak Lawn: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in Oak Lawn, with average daytime highs around 28°C. January is the coolest, when nights typically fall to about -8°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 36°C, so the seasons feel very different from each other.
The area receives about 980 mm of rain in a typical year. Most of it falls from May to August, and May is the wettest month at roughly 112 mm.
For outdoor plans and travel, September usually offers the most comfortable weather in Oak Lawn, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | 0° | -8° | 51 mm | 86% |
| Feb | 1° | -7° | 53 mm | 84% |
| Mar | 8° | -2° | 62 mm | 80% |
| Apr | 15° | 4° | 94 mm | 77% |
| May | 21° | 10° | 112 mm | 77% |
| Jun | 26° | 16° | 106 mm | 77% |
| Jul | 28° | 19° | 101 mm | 74% |
| Aug | 28° | 18° | 106 mm | 73% |
| Sep | 24° | 14° | 81 mm | 73% |
| Oct | 17° | 7° | 93 mm | 75% |
| Nov | 9° | 0° | 61 mm | 80% |
| Dec | 2° | -5° | 57 mm | 86% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around Oak Lawn. Values describe typical conditions, not a forecast.
About Oak Lawn weather
Oak Lawn, in Illinois's humid continental climate, shaped by its Great Lakes and prairie geography, is positioned about 21 km south-west of Chicago. The warmer months mean warm, humid summers (June–August). Finally, there's cold winters (December–February) with regular snow, colder near Lake Michigan. This page shows live, auto-refreshing weather for Oak Lawn: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/Chicago.
Frequently asked questions
Oak Lawn is about 21 km south-west of Chicago, in Illinois.
Oak Lawn sees cold winters (December–February) with regular snow, colder near Lake Michigan.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for Oak Lawn's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in Oak Lawn, with average daytime highs of about 28°C and nights around 19°C.
The coldest nights come in January, when the average low is about -8°C and daytime highs reach around 0°C. Frost is possible on clear, calm nights.
Oak Lawn receives about 980 mm of rain in a typical year. May is the wettest month at roughly 112 mm, and the main rainy period is May to August.
September usually offers the most comfortable weather in Oak Lawn, with mild daytime temperatures and little rain.
In November Oak Lawn typically sees daytime highs near 9°C and lows near 0°C, with about 61 mm of rain over the month and average humidity around 80%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
The current temperature for Oak Lawn updates automatically at the top of this page — scroll to the hourly strip below to see how it's expected to change over the day.
Oak Lawn's day-to-day weather follows the broader pattern of Illinois described above. See the hourly weather forecast or the air quality index for more detail.