Historical weather data, all-time temperature records, and monthly climate averages for Oak Lawn, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in Oak Lawn sits right in the heart of spring's unpredictability — the average high is a mild 54°, but this date has seen everything from 85° in 1988 to an 18° low in 1979. There's still a 7% chance of snow, so don't put the heavy jacket away just yet.
Oak Lawn earns its Midwest credentials with a staggering 132-degree swing between its all-time records: a brutal -25° in January 1985 and a scorching 107° in June 1934. A single July day in 1957 dumped 6.16 inches of rain, and a January 1999 snowstorm buried the area under 17.6 inches.
Summer is Oak Lawn's sweet spot, with highs peaking around 85° in mid-July — the same stretch that also brings the heaviest rainfall, averaging over an inch a week in late July. Winters are genuinely cold, with January highs barely clearing freezing at 31°, making May through September the clear window for comfortable outdoor plans.