Climate and monthly weather forecast
Lanark, IL

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The climate of Lanark

Lanark, a quaint city situated in Illinois, USA, features a distinct 'Dfa' Köppen climate classification, characterizing a humid continental climate with no dry season and hot summers. Weather patterns throughout the year reveal wide variations in temperature, humidity, and precipitation.

Throughout the year Lanark experiences a noticeable fluctuation in temperature, ranging from a chilly 13.5°F (-10.3°C) in January to a warm 79.9°F (26.6°C) in July. A broad spectrum of humidity levels is also detected, with values oscillating from a low of 75% in October to a high of 87% in January.

Precipitation represents an integral part of Lanark's weather pattern. The city notices rain throughout the year with the peaks becoming noticeable in May at 2.76" (70mm), followed by a decrease as the year progresses. A count of rainy days suggests the most frequent rainfall occurs from April to June, while it lessens towards the end of the year.

In the cold months, Lanark experiences snowfall, peaking at 2.64" (67mm) in January and declining to no snowfall from May to September. As for sunshine, the city is graced with the longest sunshine hours in July, extending up to 9.8 hours, and the shortest in December dropping to 4 hours.

Wind speed on average varies from 6.5mph (10.5km/h) to 10.4mph (16.7km/h), while cloud percentage registers a minimum of 32% in September and a maximum of 61% in January.

The best time to visit Lanark

Considering Lanark's weather parameters, the city's climate reaches a warm, comfortable streak between May and September. During this time, the temperature varies from a pleasant 56.5°F (13.6°C) to a maximum of 79.9°F (26.6°C), perfectly suited for outdoor explorations. Also, this period sees the least snowfall and enthusiasts of sunshine will appreciate longer sunlight hours.

The worst time to visit Lanark

Winters in Lanark are typically cold and rough, with temperature dipping as low as 13.5°F (-10.3°C) in January. Also, humidity levels remain high during these months. Combining this with considerable snowfall, it can make for a notably chilly and icy experience. Therefore, the period from November to February might not be the best time to plan a visit.

Spring weather in Lanark

Spring in Lanark presents a transition phase from the intense cold of winters to the comfortable warmth of summers. March signals the onset of spring, which runs till May, with temperature ranging from a cool 44.2°F (6.8°C) to a warmer 68.5°F (20.3°C). The city also experiences an increase in precipitation during this time, signalling the arrival of April showers.

Summer weather in Lanark

Summers in Lanark span from June to August, and are typically the hottest months of the year, with temperatures peaking at 79.9°F (26.6°C) and hardly dropping below 60.4°F (15.8°C). Despite the high temperature, humidity levels are moderate, and rainfall is less frequent, making it an ideal time for outdoor activities.

Autumn weather in Lanark

Colourful foliage and a comfortable chill mark autumn in Lanark, running from September to November. The city witnesses mild temperatures during this season, with highs of 72.9°F (22.7°C) in September to lows of 31.3°F (-0.4°C) in November. The reduced precipitation and comfortable temperatures make this season an ideal time for sightseeing.

Winter weather in Lanark

Winter in Lanark is marked by cold temperatures and snowfall. Beginning in December and ending in February, this season witnesses temperatures plunging from 32.5°F (0.3°C) in December to 13.5°F (-10.3°C) in February. The city often faces snowfall in these months, peaking in January at 2.64" (67mm).

Weather in January

Transitioning from the ending month, December, to January, there is a noticeable dip in the temperature, that marks the winter season in Lanark, Illinois, USA. The mercury usually silhouettes around 13.5°F (-10.3°C) to 25.9°F (-3.4°C), appending this period a rather icy exterior. Weather in January »

Weather in February

As January hands over the reign to February, a subtle hint of an advancing spring season can be sensed in Lanark. The days become marginally longer by around an hour, hinting at the area's transition from winter to spring. Slight inclination in temperature renders a warmer touch compared to January, although the frigid winter blanket continues to prevail with 2.2" (56mm) of snowfall. Weather in February »

Weather in March

March ushers in the city of Lanark into spring, although it bids adieu to the snowfall that catered to the scenic canvas of the winter months. With the temperature sliding up to 44.2°F (6.8°C), it declares a cessation of the biting cold that characterized the previous months. Weather in March »

Weather in April

Transition into April from March brings distinct signs of Spring in Lanark, Illinois. The temperature continues its upward climb, creating a comfortable ambiance in the city. The town experiences maximum precipitation with 1.85" (47mm) of rainfall, facilitating a plush and green vista. Weather in April »

Weather in May

As May makes its appearance in Illinois, Lanark's climate ascents towards the halcyon summer season. The distinct transition from spring culminates in a dramatic rise in mercury, yet the weather remains quite agreeable. About 14.6 hours of sunlight signifies the days in May gifting citizens with more daylight hours than any other month. Weather in May »

Weather in June

June heralds the onset of summer in Lanark, Illinois, cooling off the remnants of the spring season. As temperatures continuing to soar, it reaches the year's high of 77.2°F (25.1°C), a stark contrast from the frosty months at the start of the year. Weather in June »

Weather in July

July in Lanark, Illinois, retains the scorching effect of the summer season. With temperatures hitting a high of 79.9°F (26.6°C), July registers as the hottest month. The sun blazes in the sky for 14.9 hours, making it the second-longest day of the year. Weather in July »

Weather in August

August retains the hot summer flavor despite stepping down from the previously peaked temperatures in July. The relatively lower 60.8°F (16°C) to 78.4°F (25.8°C) temperatures mark it a transitionary phase before the onset of fall. Weather in August »

Weather in September

September in Lanark, Illinois, signifies the arrival of the fall season, with the hot summer days gradually fading out. Temperature finds a balance between the previous hot summer and the upcoming chilly winter. The month also witnesses a marginal decline in humidity from 83% in August to 79%. Weather in September »

Weather in October

October sets a quintessential autumn environment in Lanark, Illinois. The transition is marked by sylvan surroundings and cooler temperatures, replacing the summer's persistent heat. However, appreciable 1.57" (40mm) of rainfall ensures sufficient hydration for the city's exquisite fall greens. Weather in October »

Weather in November

November in Lanark welcomes the initial signs of winter, as the environment cools considerably from the warmth of October. The temperature dips, making way for the arrival of the frosty winter season. The precipitation pattern shifts from liquid to solid forms, marking the arrival of the first snow of the season, which accounts for 0.83" (21mm). Weather in November »

Weather in December

December in Illinois marks the full onset of the winter season in Lanark. The month features the return of biting cold temperatures, takings the city back to a chilling atmosphere. During this period, snowfall peaks to 1.42" (36mm), painting the city white. Weather in December »
Updated: Aug 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest month?

Lanark's January weather, with an average high temperature of 25.9°F (-3.4°C) and an average low temperature of 13.5°F (-10.3°C), tends to be the coldest of the year.

What is the most humid month?

The most humid month is January, with an average relative humidity of 87%.

What is the driest month?

The months with the least rainfall are January and February Rain falls for 4.8 days and accumulates 0.71" (18mm) of rain.

How much does it rain?

Throughout the year, in Lanark, there are 130.8 rainfall days, and 17.95" (456mm) of precipitation is accumulated.

When does it snow?

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

What is the snowiest month?

January is the month with the most snowfall. Snow falls for 11.2 days and accumulates 2.64" (67mm) of snow.

How many days does it snow?

In Lanark, Illinois, during the entire year, snow falls for 39.2 days and aggregates up to 8.62" (219mm) of snow.

What is the month with the least sunshine?

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

What is the month with the lowest UV index?

The months with the lowest UV index are January and December, with an average maximum UV index of 1.

When is Daylight Saving Time (DST)?

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?

The month with the most rainfall is May, when the rain falls for 17.9 days and typically aggregates up to 2.76" (70mm) 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 are the warmest months?

Lanark's warmest temperatures are experienced in July, with average high temperatures of 79.9°F (26.6°C) and lows of 63.3°F (17.4°C).

What month has the most sunshine?

July has the most sunshine of the year, with an average of 9.8h of sunshine.

What is the month with the highest UV index?

The month with the highest UV index is July, with an average maximum UV index of 6.

What is the least humid month?

The least humid month is October, with an average relative humidity of 75%.

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.

Average temperature
Lanark, IL

Average temperature - Lanark, IL

The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (25.9°F).

The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).

Average pressure
Lanark, IL

Average pressure - Lanark, IL

The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed
Lanark, IL

Average wind speed - Lanark, IL

The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).

Average humidity
Lanark, IL

Average humidity - Lanark, IL

The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (75%).

Average rainfall
Lanark, IL

Average rainfall - Lanark, IL

The wettest month (with the highest rainfall) is May (2.76").
The driest months (with the least rainfall) are January and February (0.71").

Average rainfall days
Lanark, IL

Average rainfall days - Lanark, IL

The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is February (4.4 days).

Average snowfall
Lanark, IL

Average snowfall - Lanark, IL

The month with the highest snowfall is January (2.64").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days
Lanark, IL

Average snowfall days - Lanark, IL

The month with the highest number of snowfall days is January (11.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight / Average sunshine
Lanark, IL

Average daylight / Average sunshine - Lanark, 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 July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days
Lanark, IL

Average sunshine days - Lanark, IL

The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is June (10 days).

Average visibility
Lanark, IL

Average visibility - Lanark, IL

The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).

Lanark, Illinois, USA

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