why is missouri so humid

Why is Missouri so humid? Typically, a relative humidity ranging from 40-60% creates a pleasant sensation. But, it is higher in Missouri most of the time.

Located in the Midwest region, Missouri experiences relatively mild winters yet warm summers, which create perfect conditions for moisture retention.

That humid climate has a direct impact on the daily lives of people in Missouri, but that raises the question, “Why is it so humid in Missouri?”

Missouri’s humidity is influenced by its proximity to the Mississippi River and other large bodies of water, prevailing wind patterns, and abundant rainfall.

More About Humidity in Missouri

more about humidity in missouri

Okay, so does Missouri have high humidity? Yes, it does.

Missouri encounters a fusion of subtropical and continental effects, leading to a moist climate.

Those high humidity levels are a result of the combination of generous rainfall and elevated temperatures.

Missouri ranks as the 13th most humid state in the United States, boasting a humidity level of precisely 82.25%.

Due to its position in the heart of the nation, the state is susceptible to a range of climatic conditions. 

States with High Humidity Levels

states with high humidity levels

Besides Missouri, a few states are notable for having the greatest average yearly levels.

Mississippi and Louisiana are considered the most humid states in the United States, whereas the list of the top five most humid states also include:

  • Georgia
  • Florida
  • Alabama

The elevated levels of humidity in these states are a result of their geographical positions.

Mississippi and Louisiana, situated on the Gulf of Mexico, encounter significant moisture levels as a result of the warm, humid air originating from the Gulf.

Furthermore, these particular states also experience substantial precipitation throughout the year, which adds to the overall level of humidity.

Something similar happens in the case of Missouri, but it still occupies 13th place on the list. 

Here are the rankings:

RankStateHumidity in %
11thSouth Carolina82.50
9thNorth Carolina82.83
8thWest Virginia83.50

Climate in Missouri

climate in missouri

The average temperatures in Missouri exhibit significant variations.

Taking into account the level of moisture in the air, the temperatures give off a cold sensation for approximately half of the year.

And for the rest of the year, they are generally pleasant with a minimal likelihood of rain.

The region has a lower temperate climate compared to other popular tourist destinations across the globe.

If you are searching for the absolute peak time to visit Missouri and experience its highest temperatures, you may consider visiting during:

  • July
  • August
  • June

Typically, the peak of summer occurs in late July when temperatures reach an average high of approximately 90.7°F (32.6°C).

Fact: Even during the summer, the nights remain relatively warm in Missouri, seldom falling below 68.6°F (20.3°C). 

Why Is Missouri So Humid?

why is missouri highly humid

Situated in the heart of the United States, Missouri is renowned for its moist weather conditions.

The region encounters elevated levels of moisture all year round, resulting in a sticky and unpleasant sensation, especially in the summer season.

Multiple elements play a role in the elevated moisture levels experienced in Missouri.

Here is more about those factors: 

Geographical Location

geographical location

The humid climate in Missouri is influenced by its geographical position in the Midwest.

In contrast to the coastal regions, the state is situated at a considerable distance from extensive water bodies that possess the ability to offer innate moisture.

Missouri encounters elevated humidity levels due to the absence of marine influence moderating effects.

Fact: Being situated away from the coast implies that it lacks the consistent oceanic gusts that coastal areas relish, which can aid in diminishing humidity levels

Weather Pattern

weather pattern

Humidity levels in Missouri experience notable fluctuations throughout the year.

In the summer season, high temperatures and regular thunderstorms contribute to a moist atmosphere.

During the summer season, the relative humidity typically varies between 70% and 85% on average.

The high humidity levels are a result of the moisture originating from the Gulf of Mexico, along with elevated rates of evaporation and thunderstorm-induced rainfall.

On the other hand, the winter season is known for its reduced humidity levels, typically ranging from 45% to 60% in terms of average relative humidity. 

An Important Consideration

Lower temperatures decrease the air’s ability to retain moisture, resulting in a limited overall moisture supply.

The fluctuation in humidity levels during different seasons showcases the ever-changing climate of Missouri. 

The Mississippi and Missouri Rivers

the mississippi and missouri rivers

The presence of the Mississippi and Missouri Rivers greatly influences the level of humidity experienced in the state of Missouri.

During the warmer months, these rivers emit water vapor into the atmosphere as vast bodies of water.

The water vapor merges with the warm air, resulting in elevated levels of humidity.

Moreover, the existence of these rivers amplifies the rates of evaporation, resulting in the liberation of additional moisture into the atmosphere.

Fact: The role of the Mississippi and Missouri Rivers in shaping Missouri's humid climate is significant. 

The Impact of the Gulf of Mexico

the impact of the gulf of mexico

Missouri is impacted by the Gulf of Mexico, which is positioned to the southern region of the state.

The Gulf of Mexico with its temperate water serves as a substantial reservoir of humidity.

In the months of higher temperatures, the dominant winds have the ability to transport this moisture towards the north.

And it eventually reaches Missouri and subsequently raises the levels of humidity within the state.

This occurrence, widely referred to as the “Gulf surge,” has the ability to carry damp air masses, which adds to the overall moisture levels in the area. 

The Role of Vegetation and Agriculture

the role of vegetation and agriculture

The humidity levels in Missouri are influenced by the state’s vegetation and agricultural practices.

Moisture is released into the atmosphere through transpiration, a natural process in which plants emit water vapor from their leaves.

Due to the abundant plant life in Missouri, a substantial quantity of moisture is emitted into the atmosphere.

Furthermore, forests have a crucial impact on maintaining humidity levels through their ability to offer shade and decrease rates of evaporation.

Missouri experiences increased humidity due to the presence of plentiful plant life and farming practices.

Fact: An individual corn plant has the ability to emit approximately 50 liters of water per day through the process of transpiration, adding to the overall humidity levels. 

Urbanization and Human Activities

urbanization and human activities

As urban areas continue to grow in Missouri, the actions of humans are causing a rise in humidity levels.

Urban areas often experience the phenomenon known as the “urban heat island effect” due to the heat absorption and retention properties of concrete and asphalt surfaces.

This phenomenon results in specific regions experiencing higher temperatures compared to nearby rural areas.

This results in elevated rates of evaporation and subsequently increased levels of humidity.

Many activities have the potential to increase moisture levels in the air, such as:

  • The usage of air conditioning systems
  • Various industrial processes
  • The emissions produced by vehicles

And all these activities also have a role to play in pushing humidity levels up in Missouri

Impact of Humidity on Comfort and Health and How to Manage It?

The substantial impact of the elevated humidity levels in Missouri on well-being and comfort cannot be overstated.

Excessive moisture in the atmosphere creates a sensation of heaviness in the air, leading to potential unease.

humidity's impact on comfort health and management

This is especially true in the summer season when temperatures are already elevated.

This can create challenges for the body in terms of cooling down through the process of sweat evaporation, resulting in sensations of stickiness and heightened exhaustion.

Furthermore, elevated moisture levels create a perfect setting for the proliferation of fungi, mold, and microscopic organisms like dust mites.

These factors can potentially exacerbate respiratory problems and trigger allergic reactions.

Here is what you can do to overcome these issues:

Key Factors Managing HumidityHow Does It Helps?
Proper ventilationRemoves excess moisture from the air
HVAC systemsExtracts moisture from the air
Sealing air leaks and insulationPrevents humid air from entering the house


Why is Missouri so humid? While Missouri is not the most humid state in the United States, it can still get extremely humid in this part of the world.

In fact, humidity can go beyond 80% in the summer, which is quite high.

And all this happens due to its geographical location and close proximity to the Mississippi River and other bodies of water.

And of course, vegetation and the urban heat island effect also have a role to play.