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The Most Humid Cities in the U.S. & How to Prevent Damage to Your Home

Written by Charlotte Granville

Published on April 3, 2023


The Most Humid Cities in the U.S. & How to Prevent Damage to Your Home

We reveal the top 50 most humid cities in the country, the signs of high humidity in your home, and home improvements to protect your home from moisture damage.

To provide you with the most accurate and up-to-date information, we consult a number of sources when producing each article, including licensed contractors and industry experts.

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Living in a humid city comes with the added necessity of taking action to protect your home. A comfortable humidity level is considered to be between 30% and 50%, and it’s actually important for your home to stay within this range, as high humidity can cause damage in the long run. If there’s too much moisture in the air, your home could be prone to mold, rot, and other interior damage.

In this article, we’ll reveal some of the most humid cities in the U.S., along with the signs of high humidity in the home and which home improvements can help prevent damage.

We collected data from the NOAA to calculate the average annual humidity of some of the largest cities in the U.S. The above map highlights the data’s top 50 cities with the highest humidity levels in the country. According to the data, San Francisco is the most humid city on average, with an annual humidity level of 78%. This could be compared to Las Vegas, which was recorded to be one of the driest cities in the U.S., with an average humidity level of 28%.

If you happen to live in or around any of these top 50 most humid cities, you should consider investigating the humidity levels in your home to prevent any damage. 

Below, we go into detail about what to look out for to know if humidity is affecting your house. 

The Signs of High Humidity in Your Home

According to the Building Performance Institute, humidity levels between 62% and 93% inside the home can cause serious damage to its structure and integrity, so it's important to keep track of the air conditions in every area of your home. There are ways to measure indoor humidity, such as digital thermometers or hygrometers, but there are some telltale signs that the humidity levels inside your home are too high. 

Toxic mold

Mold usually appears around HVAC systems, appliances, windowsills, shower walls, and faucets. It is a key indicator that your home has a moisture problem. You know you have mold in your home if you can spot dark staining and fuzzy growth on surfaces, which can produce a musty smell. Certain types of mold can be toxic, so it’s important to tackle this problem as soon as you see signs of growth. 


If the moisture levels are high in certain areas of your home, condensation will deposit onto surfaces with a slightly lower temperature, such as windows. If you notice condensation forming on the inside of your windows, it’s a sign of too much moisture in the air. It’s important that you don’t ignore this early sign of excess moisture, as it can encourage mold growth and damage your windows’ integrity. 

Damaged paint or peeling wallpaper

Condensation can also occur on walls, causing paint or wallpaper to get wet. If condensation is affecting your walls, you’ll notice some damage to the paint or peeling of the edges of the wallpaper. Moisture on the walls can potentially seep through and damage your home's structure, so pay attention to this sign of high humidity.

Rotting wood

Wood tends to be prone to damage from moisture, so if your home is subjected to high humidity, then stains can appear on wooden surfaces or furniture. In more severe cases, wood can rot, which can cause extensive damage to wooden floors and windows. So to avoid costly repairs to these features, it’s worth considering some home improvements that will prevent high humidity inside your home. 

How to Prevent High Humidity in Your Home

A dehumidifier can help reduce the moisture in the home, but there are more efficient and permanent ways to solve this problem. Certain home improvements can prevent high humidity in the home and offer you peace of mind in terms of any damage being caused by excess moisture in the air. 

Removing Moisture From the Air With a Bathroom Fan

The bathroom is one of the most humid spaces in the home. With steam and condensation depositing on walls and surfaces, excess moisture can start causing damage, or mold can begin to build up. Installing a bathroom fan will help keep the room ventilated and remove some moisture from the air. These vent fans can also prevent bad odors created by humidity and dampness.

Cost: A bathroom fan installation costs an average of $350.

Insulating Your Home

People often underestimate the power of proper home insulation. It can significantly reduce your energy bills by retaining heat in the winter and maintaining a cool temperature in the summer. It can also prevent humid air currents from entering your home. If you live in a humid area, insulating your home will help keep out moisture from outside and improve the overall air quality of your home. 

Cost: Home insulation costs anywhere from $3,000 to $7,000 on average.

Replacing Your Windows

As with insulation, your windows need to be able to keep any humid air currents from entering your home. Old windows can let in drafts and cause thermal transfer, affecting indoor temperature and humidity. Replacing your windows will not only increase energy efficiency, but it will also help regulate the moisture levels inside your home. 

Cost: Window replacement costs vary between an average of $3,500 and $10,500.

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If it rains a lot in your area, keeping the drainage around your home’s foundation in check is important. Improper drainage will increase the humidity around your home and, in turn, cause damage to outdoor features. One way to improve drainage is to ensure any soil around your home slopes away from the foundation to avoid any water pooling. A professional landscaper can do this and will help decrease the humidity inside and outside of your home.

Cost: Landscaping costs can run between $8,000 and $15,000 on average. 

Protecting Your Home From Costly Damage

Even if you don’t happen to live in one of the most humid cities in the U.S., keep track of the humidity levels in your home to avoid any damage. If you’re concerned about the humidity levels in your home, you can have a thermal imaging inspection carried out by a professional, which will help identify any issues in terms of moisture so you can fix them before they cause too much damage. 

The costs to improve your home to protect it from high humidity will be worth avoiding the costly repairs needed from the damage excess moisture can cause. Ensuring your home is protected from high humidity is important for both the integrity of your property and your health and well-being.


We collected data from the NOAA on some of the largest cities in the United States by population. We analyzed this data and calculated the average annual relative humidity level of 263 cities, revealing the top 50 most humid cities in the U.S.


Charlotte is a home remodeling specialist at Fixr.com. With a Bachelor’s degree in Visual Communications, she analyzes industry data to provide homeowners with the best advice and visual representations of the home improvement sector. She is passionate about promoting sustainability within the home, and with a personal interest in interior design, she is always up to date about the latest home remodeling trends.