From Florida to California: Which States Have the Worst Summer Humidity (And What You Can Do About It)

We equate summers with heat, but high temperatures and long hours of bright, hot sunlight aren’t the only things to watch out for. In some regions of the US, heat isn’t even the biggest problem. Humidity is.

Humidity 101

Humidity is the measure of moisture in the air. High humidity is responsible for the icky, sticky feeling that often pervades in summer when the sun is high and the air feels thick and heavy with moisture.

The rule with humidity is that the higher the temperature, the higher the air’s capacity to hold moisture. Logically, this means that all hot places are humid. But this isn’t always the case.

Other factors like elevation, surrounding terrain, weather, and proximity to large water forms like lakes and oceans, also come into play. The variations in these factors affect humidity levels in certain states, which explains why New Mexico has relatively dry summers.

While, right next to it, Texas, has stiflingly humid summers—so much so that professional dehumidifiers are just as vital as air conditioning for Texans.

Humidity does not just make hot days more uncomfortable; it can also do a number on your health and well-being. But we shall save the in-depth discussion on the negative health effects of humidity for another blog.

For now, let’s discuss which US states are the most humid in summer, why humidity makes summers uncomfortable, and tips on what you can do to make humid summers more bearable.

Summer In the United States

The first thing to bear in mind when discussing the climate in the US is that the country is a massive land mass. Excluding the Caribbean islands, there are four more major countries in North America, and the US occupies nearly 40% of the total land area. Its territory stretches from the eastern to the western coast of the continent. Because of this, seasons in the US vary across regions and states.

Summer in the US starts in June and ends in August, and the climate ranges from warm to stiflingly hot. Additionally, regions next to the coastlines are usually more humid and therefore have more stiflingly warm summers.

In the Midwest and northern states of Montana and Idaho, for example, early mornings and evenings are cool, but temperatures could spike in the middle of the day. The temperature changes lead to fluctuations in humidity, so having an efficient energy dehumidifier and cooling system is important for staying cool and comfortable throughout the day.

It gets hotter and stuffier in the eastern and southern states, especially in tropical areas. There, humidity levels can go up to the high 70’s. Locals often get a double-whammy during summer: days can get so hot and humid, it can be hard to breathe when walking outside during the day.

Humidity levels also increase indoors, making efficient crawlspace dehumidification just as crucial as central air conditioning in houses and commercial buildings.

The Most Humid States in the US

Which US state is too humid in summer? Take a look at the latest data from World Population Review ranking the Top 10 most humid states in the US in 2025.

The website also provided the figures for the average dew point for each state.

Dew point is the temperature at which the relative humidity is at 100%, or the temperature at which water vapor will condense and become dew. When the dew point is high (over 60°F), the day tends to feel stickier and hotter.

Many consider the dew point as a more accurate gauge on how humid the day would feel. Those who have a crawl space dehumidifier at home can attest that when the dew point is high, it collects more water than if dew point is low, regardless of the humidity rating.

 

Based on this data, Florida, which is often used as an example for US summers, is as hot and humid as people expect.

How bad is the humidity during the summer in Florida? It ranks second highest in the US for average dew point and average humidity, which is at 74.5%. Four out of the 10 major cities with the highest relative humidity are in Florida (Jacksonville, Orlando, Tampa, and Miami), and all of them averaged over 73% RH.

For context, anything over 60% RH, coupled with high temperatures, feels stifling. Living in a Florida home definitely calls for a whole-house AC and crawl space dehumidification system.

Louisiana, Mississippi, and Hawaii are also consistently in the Top 5 for both Humidity and Dew Point rankings. Together with Florida, these are the four states with the worst summer humidity in the US.

Alaska ranks fifth on dew point and 11th on humidity, so we can also consider it one of the more humid states to be in during summer.

Alabama is a unique case. The state has record-level heat and humidity, and it gets up to 65 inches of rainfall anually. However, due to atmospheric pressure patterns and movements of weather systems over the continent, Alabama can have months of dry spells and drought.

This explains why the state ranks last for dew point at only 26.5°F. Summers are extremely hot here, but on some days, you likely won’t get too sweaty or sticky.

The 100th Meridian

The 100th meridian is a simple, old method of determining which states stay relatively dry in summer versus states that get lots of rain and monsoons.

Historically, the 100th meridian marks the boundary between the lush, moist regions (East) and the dry, arid terrains (West). But as early as 2018, geologists and climate scientists at Columbia University noted that the climate boundary is shifting eastward. They noticed that the arid land mass of the Midwest is growing while the agriculture-friendly regions in the eastern half are shrinking.

There are many reasons for this phenomenon, like land developments (or the lack thereof), population growth, and climate change.

The image above is from State of the Planet, the online publication of Columbia Climate School.

Keeping in mind the scientists’ observations, we can deduce that the eastern sides of the states that straddle the 100th meridian — North and South Dakota, Nebraska, Kansas, Oklahoma, and Texas — are more humid than their western halves. The states further ahead in the Central Midwest are the dry states.

However, if you travel from the Midwest to the West Coast, you’ll find that it suddenly gets wetter and more humid in certain areas, like in Coeur d'Alene and the northern part of Idaho, where the humidity varies all year. It gets hot and arid in some months, then moist and humid towards December. Further in the northwest, Washington DC is also humid, especially during summer.

Interestingly, Oregon and California, which are coastal and theoretically should get more moisture, are known for having dry summers. This is because they have a Mediterranean climate, which gives them dry summers and wet winters.

High-pressure atmospheric systems prevail over these areas during summer, creating stable conditions that keep out low-pressure systems, the presence of which signals the start of cyclone cycles.

So, which states have the worst summers?

Cross-checking the rankings of states with the highest humidity and dew point as published on the World Population Review website with the 100th Meridian map, it is obvious that states near The Great Lakes and on the eastern coast have the most humid summers than the Midwest region. You’ll want to avoid vacationing in these states if you find high humidity in summer oppressive.

Why Does Humidity Make Hot Days Feel More Miserable?

Have you wondered why some days feel hotter than the temperature the weather app on your phone is showing? This happens when humidity is high. The air is saturated with water vapor, making it feel heavy and oppressivThis is also why it feels like a huge effort to breathe in humid air. Additionally, the saturated air slows down the evaporation of sweat, stopping the body’s natural cooling process. The sweat sitting on your skin, combined with the heat, makes one feel sticky and uncomfortable.

Fortunately, there are ways to keep cool and comfortable on humid summer days.

Tips for Managing Indoor Humidity

It’s important to keep humidity inside your house under control, especially if you live in one of the humid states listed above. Left unchecked, excessive humidity can make you feel uncomfortable all summer and negatively affect your health.

Below are the common adverse health effects of exposure to heat and humidity:

• Overheating
• Dehydration
• Heat exhaustion
• Dizziness
• Fatigue
• Muscle cramps
• Extreme discomfort
• Foul mood and restlessness
• Allergy flare-ups Increased stress

Persistent indoor humidity can also increase the risk of exposure to mold toxins. If dampness has been a constant problem in a house, there is a good chance that mold is already lurking behind the drywall and plaguing people who are sensitive to mold spores.

The good news is that indoor humidity can be managed. With the right equipment and preventive routine, you can keep indoor humidity low and ensure your household’s comfort, especially in summer.

Here are some tips on how to reduce indoor humidity:

• Invest in a powerful, energy-efficient dehumidifier for the main rooms of your house. Together with an AC, it will solve moisture problems in your home.
• Get a crawl space dehumidifier if you live in one of the country’s most humid states. Moisture from a humid crawl space can spread to the upper floors unnoticed and cause structural problems over time. Installing a low-consumption, high-efficiency energy dehumidifier inside your crawl space or basement will prevent moisture and mold from wreaking havoc on your property and compromising your health and comfort.
• Open your windows to improve air circulation. Even better, open windows on opposite sides of your house as this allows a breeze to pass through your home. It's great for lowering humidity and getting rid of the stale air inside your house.
• Speaking of air circulation, install ceiling fans or buy portable fans if you’re looking for cheaper alternatives to central air conditioning.
• Look for leaks and other sources of unnecessary moisture, like faulty gutters and cracked plumbing, and have them repaired.
• Look for gaps or breaks in the weather stripping around your windows, window frames, and doorframes. Seal them to prevent hot air from entering and condensing on the cool surfaces inside your air-conditioned house.
• Install exhaust fans in the kitchen, bathroom, and laundry area if possible. Turn them on whenever you’re cooking, taking a hot shower, or using the dryer.

What Should Be the Humidity Level at Home?

“What should the humidity be in my house in the summer?”

The ideal range for indoor humidity is between 30% and 50%, according to SleepFoundation.org and the National Asthma Council Australia. Health academics and researchers extend the permissible range to 60%, but there is a wide consensus that anything over 60% is no longer ideal. Not only is it uncomfortable, but it also creates a viable environment for viruses, mold, and bacteria.

Heat is also a factor for comfort. For example, if the temperature goes higher than 80°F, humidity over 40% will already feel uncomfortable.

Play it by ear: if the day is hot, crank up the AC to ward off the heat. If your home still feels stuffy, turn on a professional dehumidifier for at least one hour to reduce indoor moisture and freshen the air.

Alternatively, you can keep the AC at your usual settings and simply switch on the dehumidifier to draw out moisture. Find a combination of settings that create the indoor environment you like best, and you’ll be fine no matter how hot or humid the weather gets.

From Summer to Autumn, Don’t Let Humidity Get in the Way

Outdoor humidity is out of our hands, but indoor humidity can entirely be in our control. Even if you live in the country’s hottest and most humid states, humidity can’t muck up your summer if you know how to address indoor humidity and are equipped to combat excessive moisture.

Argendon is a great place to start. Our crawl space and standing dehumidifiers are ideal for year-long crawl space dehumidification; summer humidity is no match for our professional dehumidifiers.

Browse our website and get in touch with our customer service team if you have questions about our products, availability, delivery, and more.

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