why is it so humid in chicago

Why is it so humid in Chicago? Undoubtedly, Chicago is the city that likes to keep you on your toes with its ever-changing weather.

And let us not forget about the humidity, the special ingredient that makes every day feel like a sauna.

Chicagoans get to experience the joys of beach weather without ever leaving the city thanks to the high humidity levels. But, why exactly is that?

Chicago’s weather is quite complex due to the interaction of various air masses, which also contributes significantly to the city’s overall humidity. 

Why is It So Humid in Chicago?

reasons of high humidity in chicago

When you think about visiting Chicago for the first time, it is natural to ask, “Is Chicago humid or dry?”

Well, the truth is that the weather in Chicago can be quite extreme. But, is Chicago humid?

It certainly is, and here are some of the reasons why: 

Geographic Location and Climate

The humidity levels in Chicago are greatly influenced by its proximity to the Great Lakes, particularly Lake Michigan.

Due to its expansive surface area and warm temperatures in the summer, Lake Michigan is a prime location for evaporation to occur at a heightened rate.

geographic location and climate

When the sun’s heat touches the surface of the lake, the water molecules change into steam and ascend into the sky.  

Fact: Chicago's high humidity records hold no significance as the area has experienced 100% relative humidity multiple times, particularly during dense fog situations.

The Effect of the Urban Landscape

When the humid air travels towards the city from Lake Michigan, it comes across the urban landscape of towering buildings, highways, and various constructions.

These characteristics disturb the typical air currents and obstruct the spread of dampness.

As a result, the air filled with moisture gets confined within the city, leading to increased humidity levels in Chicago.

An Important Consideration

It is common for the dominant winds to come from the east, resulting in the regular transportation of moist air from the lake towards the urban area.

The unceasing arrival of damp air intensifies the level of humidity felt by the inhabitants of Chicago and adds to the sticky atmosphere that is widespread in the region. 

Continental Climate

continental climate

The humidity levels in Chicago are greatly impacted by its position within the continental climate zone.

Distinct seasonal changes can be observed in the city, characterized by hot and humid summers and cold winters.

Chicago’s climate and humidity patterns are significantly influenced by the interplay of warm and moist air masses from the Gulf of Mexico and cold fronts from the north.

Chicago experiences an influx of warm and humid air masses during the summer season, which originates from the Gulf of Mexico and travels northward.

The city’s humidity is caused by the abundance of moisture present in these air masses.

When warm and moist air masses meet with cold fronts coming from the north, they clash and give rise to thunderstorms. 

High Humidity in the Summer

high humidity in the summer

Chicago summers are often marked by thunderstorms that result in significant precipitation in the area.

Heavy rainfall not only adds to the total amount of precipitation but also raises the moisture content in the air.

Chicago residents experience high levels of humidity during the summer season due to the warm and moist air, as well as the frequent thunderstorms. 

Urbanization and Heat Island Effects

urbanization and heat island effects

The urban heat island effect in Chicago is significantly influenced by the city’s urbanization, which affects its humidity levels.

Chicago is a bustling metropolis with towering skyscrapers, sprawling highways, and a predominantly concrete and asphalt infrastructure.

The heat capacity of these building materials is quite high, which enables them to effectively absorb and retain heat.

The city’s surfaces soak up a lot of heat during the day due to the constant exposure to sunlight.

During the night, the heat is released into the atmosphere, causing the city to experience high temperatures and humidity levels.

Fact: The swift growth of cities frequently leads to transforming natural landscapes into urban environments, which can worsen the already high humidity levels. 

Humidity in Downtown Chicago Due to Urban Heat Island Effect

chicago's urban heat island and humidity

Research has indicated that the urban heat island phenomenon can cause a rise in temperatures in densely populated regions, like downtown Chicago.

In fact, the difference may be by a few degrees in contrast to nearby rural zones.

The humidity levels worsen due to the extra heat, as warm air has the ability to retain more moisture. 

Reduced Green Spaces

reduced green spaces

Chicago’s urban development has led to a decline in the availability of green spaces, including parks, gardens, and other areas with vegetation.

The decrease in plant life has noteworthy consequences for the moisture levels within the urban area.

Transpiration is a crucial process through which plants release moisture into the atmosphere, thereby regulating humidity levels.

Plants play a crucial role in regulating moisture levels in the environment.

They absorb water from the soil and release it into the atmosphere through their leaves, making green spaces an important factor in this process. 

An Important Consideration

Research has shown that incorporating green spaces in cities can effectively decrease humidity levels and enhance air quality.

Having trees, grass, and other types of vegetation around can create a pleasant and well-balanced microclimate by cooling the air.

Fact: The process of evapotranspiration plays a crucial role in preserving the moisture equilibrium in the nearby surroundings and balancing humidity levels. 

Interaction of Air Masses

interaction of air masses

Due to its position on the map, Chicago experiences a mix of different air masses that collide, resulting in ever-changing weather patterns and higher levels of humidity.

Cold air masses from Canada move southward into the area, resulting in cooler and less humid weather.

At the same time, warm and moist air masses from the Gulf of Mexico move towards the north, bringing with them elevated levels of humidity and temperature.

As soon as these distinct air masses collide, they produce a demarcation called a front, which can serve as a center for convective activities and the emergence of thunderstorms.

The convective patterns not only result in substantial precipitation but also increase the region’s moisture levels. 

Lake Breezes

lake breezes

During the summer months, Chicago is affected by lake breezes, which is a unique phenomenon.

When the sun warms up the ground, the surrounding air also heats up and rises, resulting in the formation of a low-pressure zone.

As a result of the low-pressure system, a refreshing lake breeze is created by the influx of cooler air from Lake Michigan.  

Chicago’s humidity levels are significantly impacted by the influx of cooler, moisture-laden air from Lake Michigan.

The increased level of moisture intensifies the prevailing humidity, resulting in a moist environment.

Lake breezes can significantly impact the metropolitan area, extending several miles inland and affecting a large portion of the city. 

Rising Global Temperatures

rising global temperatures

Climate change is causing a rise in global temperatures, which has a notable impact on humidity levels not only in Chicago but also in other parts of the world.

With the rise in temperatures, there is an increase in the amount of heat that can facilitate evaporation, leading to a surge in the moisture levels present in the atmosphere.

The increased moisture levels result in elevated humidity levels that are felt in various regions, such as Chicago. 

An Important Consideration

In cities such as Chicago, it is essential to take necessary actions to combat the challenges of climate change.

This should include adjusting to the shifting climate and implementing strategies to alleviate the impact of increasing temperatures and humidity.

Fact: The alterations in weather conditions and rise in moisture levels have consequences for well-being, convenience, and city development.  

Extreme Weather Events

extreme weather events

Climate change worsens the frequency of extreme weather conditions in Chicago, apart from the increasing temperatures.

Sudden spikes in humidity can occur due to heavy rainfall and severe storms, which are increasing in frequency and intensity.

Excessive weather occurrences lead to a considerable increase in moisture in the air, causing the humidity levels in the urban area to escalate even more.

Chicago’s humidity is intensified by the changing climate patterns, which amplify the pre-existing factors.

With the increasing frequency of extreme weather events, it is essential for cities to take necessary measures to cope with these conditions. 


Why is it so humid in Chicago?

Chicago’s elevated humidity levels are a result of various geographical elements, including its nearness to the Great Lakes, the interplay of air masses, and the urban heat island effect.

Understanding what causes high humidity levels in Chicago is important as it helps ensure the comfort and safety of the residents.

And it becomes more important in the face of high humidity and other weather-related challenges we face today.