Climate and monthly weather forecast
Oak Lawn, IL

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The climate of Oak Lawn

Oak Lawn, situated in Illinois, USA, lies within a Humid continental climate region, under the Köppen climate classification denoted as Dfa. This signifies hot summers and no dry season. Pervading temperatures in Oak Lawn vary considerably during the yearly cycle, and the region regularly experiences humidity, rain, and snow.

The annual high temperatures fluctuate from 29.5°F (-1.4°C) in January to 81°F (27.2°C) in July, while the lows oscillate from 18.9°F (-7.3°C) in January to 66.6°F (19.2°C) in July. Similarly, the relative humidity levels in the area stay quite steady throughout the year, maintaining between 72% in October and 82% in January and February. The total yearly rainfall averages 2.21" (56mm), with the wettest month being May, receiving around 3.07" (78mm) of precipitation, and December getting the least, at approximately 1.02" (26mm). Meanwhile, snowfall is distinctly seasonal, wholly taking place from November through April, with the heaviest snow in February, totaling 3.07" (78mm).

An examination of sunlight hours shows that June offers the longest days, with 15.2 hours of daylight, contrarily, the shortest days happen in December, having about 9.2 hours. Consistent with this, the UV index reaches its peak of 6 between June and August, while it descends to 1 in December. Meanwhile, wind speeds are relatively moderate throughout the year, reaching their highest average rate of 10.6mph (17.1km/h) in January and decreasing to their lowest of 6.5mph (10.5km/h) in August.

Overall, the climate in Oak Lawn features a distinctive seasonal pattern, marked by hot summers and cold winters, regular rainfall and snowfall, and consistent humidity levels. This results in diverse weather patterns throughout the year.

The best time to visit Oak Lawn

May to September marks an advantageous period to visit Oak Lawn. This phase experiences warm to mildly hot temperatures, with highs ranging from 66.4°F (19.1°C) to 81°F (27.2°C) and lows hovering from 51.8°F (11°C) to 66.6°F (19.2°C). This period is also the sunniest, offering between 10.3 hours to 10.5 hours of sunshine per day from June to August. This agreeable weather makes it an optimal timeframe for outdoor activities.

The worst time to visit Oak Lawn

The period from November through February can be considered the least desirable for visiting Oak Lawn, as it experiences the coldest temperatures. Average highs sink to between 29.5°F (-1.4°C) and 46.2°F (7.9°C), and lows can plunge to from 26.4°F (-3.1°C) to 35.1°F (1.7°C). Additionally, snowfall is highest across these months, thereby severely restricting outside activities.

Spring weather in Oak Lawn

Spring in Oak Lawn transpires from March to May. This season shows a progressive climate shift as temperatures climb from an average high of 44.2°F (6.8°C) and low of 32.4°F (0.2°C) in March to a high of 66.4°F (19.1°C) and low of 51.8°F (11°C) in May. Further, rainfall tends to intensify in this season, culminating in May with an average of 3.07" (78mm), and daylight hours increase, reaching 14.6 hours by season's end.

Summer weather in Oak Lawn

June through August denotes Oak Lawn's summer months. These are the hottest and sunniest months, with average highs oscillating from 76.3°F (24.6°C) to 81°F (27.2°C) and lows from 61.5°F (16.4°C) to 66.6°F (19.2°C). June offers the longest daylight hours with 15.2 hours. Nonetheless, summers also bring substantial rainfall, averaging around 2.89" (73mm) per month.

Autumn weather in Oak Lawn

Autumn in Oak Lawn, running from September to November, manifests a gradual cooling trend, with an average high temperature decreasing from 73.6°F (23.1°C) in September to 46.2°F (7.9°C) in November. Equally, lows dwindle from 59.2°F (15.1°C) to 35.1°F (1.7°C) within the same timeframe. Despite rainfall reducing to an average of 1.69" (43mm) monthly, the sunshine hours decrease significantly, dwindling from 9.1 hours in September to 5.1 hours in November.

Winter weather in Oak Lawn

Winter months in Oak Lawn, December through February, amass the coldest temperatures and substantial snowfall. Average highs drop to between 29.5°F (-1.4°C) and 35.2°F (1.8°C), while lows tumble to from 26.4°F (-3.1°C) to 18.9°F (-7.3°C). Moreover, these cold months also observe an average snowfall amounting to 2.52" (64mm). Hence, Oak Lawn's winter season is characterized by high humidity, low sunshine hours, and cold temperatures.

Weather in January

January in Oak Lawn, Illinois is characterized by a chilly atmosphere with the lowest temperature in the year reaching 18.9°F (-7.3°C). A steady pattern of snowfall gives the city a white blanket, making it a winter wonderland. Weather in January »

Weather in February

Despite a slight increase in temperature, February remains quite cold, resembling January's weather conditions. Snow continues to rule the forecast with residents bracing for more inches. The daylight hours increase, yet the days are still relatively short. Weather in February »

Weather in March

March signals the arrival of spring, and the transition in weather from chilly winters to slightly warmer forecasts is apparent. The snow starts to diminish, giving way to rain as the primary form of precipitation. High humidity remains persistent, contributing to the dampness in the atmosphere. Weather in March »

Weather in April

April brings a substantial uptick in temperature to Oak Lawn, marking firm arrival of Spring. There's a substantial increase in rainfall from 1.3" (33mm) to 2.32" (59mm), making the city feel fresh, albeit a bit damp. The extended daylight hours provide ample opportunities for outdoor activities. Weather in April »

Weather in May

May experiences considerable warming in Oak Lawn, with pleasant temperatures offering a break from the rainy April. Signifying the advent of summer, the city enjoys maximum daylight hours. The weather is fairly consistent, fetching stable days. Weather in May »

Weather in June

Oak Lawn welcomes the start of summer in June with significantly heightened temperatures. The days become the longest of the year, with sunshine dominating most of the daylight hours. Humidity levels rise slightly, lending an increased warmth to the extended days. Weather in June »

Weather in July

July is the height of summer in Oak Lawn, basking in high temperatures reaching up to 81°F (27.2°C). Extended daylight hours and high UV index necessitate protection against sunburn. Despite the sometimes intense heat, the weather remains fairly consistent, keeping the city bustling with activity. Weather in July »

Weather in August

In August, Oak Lawn continues to simmer in summer heat, albeit a slight decrease in temperature. Slightly higher humidity raises the heat index, making days feel hotter than actual. Despite the decrease in sunshine hours, days remain long and filled with light. Weather in August »

Weather in September

September rings the curtain down on summer, bringing a considerable reduction in temperature in Oak Lawn. The onset of fall can be felt with cooler weather and shorter days. Rainfall decreases, providing relief to those weary of the summer showers. Weather in September »

Weather in October

October in Oak Lawn is a beautiful spectacle with fall colors adorning the city's landscapes. Temperatures further drop, bringing in cool and crisp weather. Rainfall continues its downward trend, paving the way for clear days ahead. Weather in October »

Weather in November

November witnesses a marked drop in temperature, signaling the onset of winter in Oak Lawn. The first hints of snow appear, replacing the rain and giving the city a frosty look. Fall colors start giving way to white snow, altering the cityscape. Weather in November »

Weather in December

December marks the introduction of intense winter in Oak Lawn, Illinois with temperatures dropping to 35.2°F (1.8°C). Snowfall dominates the landscape, providing a white Christmas to the city. Despite the falling temperature and decreasing daylight, the city glows with festive lights and holiday spirit. Weather in December »
Updated: Jun 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the coldest months?

January stands out as Oak Lawn's coldest month, with an average high-temperature of 29.5°F (-1.4°C) and a low-temperature of 18.9°F (-7.3°C).

What are the most humid months?

January and February, with an average relative humidity of 82%, are most humid months.

How much does it rain?

In Oak Lawn, Illinois, during the entire year, the rain falls for 147.7 days and collects up to 23.62" (600mm) of precipitation.

When does it snow?

Months with snowfall are January through April, October through December.

How many days does it snow?

Throughout the year, there are 42.4 snowfall days, and 11.61" (295mm) of snow is accumulated.

What is the month with the least sunshine?

The month with the least sunshine is January, with an average of 3.7h of sunshine.

When does it snow the most?

The month with the most snowfall is February, when snow falls for 9.5 days and typically aggregates up to 3.07" (78mm) of snow.

When is Daylight Saving Time (DST) in Oak Lawn?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

What is the wettest month?

May is the month with the most rainfall. Rain falls for 17.7 days and accumulates 3.07" (78mm) of precipitation.

When it does not snow?

May through September are months without snowfall.

When are the longest days?

The month with the longest days is June, with an average of 15h and 12min of daylight.

What is the month with the highest UV index?

June through August, with an average maximum UV index of 6, are months with the highest UV index.

What are the warmest months?

July tends to be the warmest month, with temperatures averaging a daily high of 81°F (27.2°C) and a low of 66.6°F (19.2°C).

What month has the most sunshine?

The month with the most sunshine is August, with an average of 10.5h of sunshine.

What is the least humid month in Oak Lawn?

The least humid month is October, with an average relative humidity of 72%.

What is the driest month?

The month with the least rainfall is December, when the rain falls for 7.4 days and typically collects 1.02" (26mm) of precipitation.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 12min of daylight.

When is the lowest UV index?

The month with the lowest UV index is December, with an average maximum UV index of 1.

Average temperature
Oak Lawn, IL

Average temperature - Oak Lawn, IL

The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (29.5°F).

The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

Average pressure
Oak Lawn, IL

Average pressure - Oak Lawn, IL

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed
Oak Lawn, IL

Average wind speed - Oak Lawn, IL

The windiest month (with the highest average wind speed) is January (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).

Average humidity
Oak Lawn, IL

Average humidity - Oak Lawn, IL

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).

Average rainfall
Oak Lawn, IL

Average rainfall - Oak Lawn, IL

The wettest month (with the highest rainfall) is May (3.07").
The driest month (with the least rainfall) is December (1.02").

Average rainfall days
Oak Lawn, IL

Average rainfall days - Oak Lawn, IL

The month with the highest number of rainy days is July (18 days).
The month with the least rainy days is February (4.9 days).

Average snowfall
Oak Lawn, IL

Average snowfall - Oak Lawn, IL

The month with the highest snowfall is February (3.07").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days
Oak Lawn, IL

Average snowfall days - Oak Lawn, IL

The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight / Average sunshine
Oak Lawn, IL

Average daylight / Average sunshine - Oak Lawn, IL

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days
Oak Lawn, IL

Average sunshine days - Oak Lawn, IL

The month with the most sunshine days is November (17.5 days).
The month with the least sunshine days is July (9.8 days).

Average visibility
Oak Lawn, IL

Average visibility - Oak Lawn, IL

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Oak Lawn, Illinois, USA

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