Why Humidity Increases at Night: We Find Out

If you’re like most people, you probably don’t think about humidity levels until they become a problem. And, unfortunately, high humidity levels at night can cause all sorts of common sleep challenges. Let’s explore the reasons why humidity increases at night.

Humidity increases at night as the ground cools off more quickly after sunset than the air above it. This temperature difference causes the air to flow towards the ground, picking up moisture as it does so. Plants also release water vapor into the air through a process known as transpiration.

Why Humidity Increases at Night - Moon Over Ocean

Imagine that you’re trying to get to bed on a hot, summer night. You’re sticky and sweaty, and you can’t seem to get comfortable. You toss and turn for hours, but you can’t seem to fall asleep. It’s no wonder humidity levels at night can have such a big impact on our sleep!

It can be really uncomfortable to sleep in a room that’s too hot and humid. You’re sticky and sweaty, and you can’t seem to get comfortable. Plus, high humidity can cause your body to overheat, making it difficult to fall asleep.

In addition, high humidity can lead to problems with allergies and asthma. The moist air can aggravate respiratory problems and make it difficult to breathe.

So, what can you do if you’re having trouble sleeping because of high humidity levels? Here are a few tips:

  • Invest in a good quality air conditioner or dehumidifier. This will help to keep your room cool and dry.
  • Open the windows and let in some fresh air. This will help to lower the humidity level in your room.
  • Increase the ventilation in your home by using fans or an attic ventilator. This will help to circulate the air and reduce moisture levels.
  • Sleeping with a wet washcloth on your forehead can also help to cool down your body and lower your internal temperature.

Humidity can also cause mold and mildew to grow in your home, which can lead to a number of serious health problems, including respiratory infections and allergies.

Why Humidity Increases at Night

The air is generally more humid at night than during the day for a few reasons. The ground cools off more quickly after sunset than the air above it. This temperature difference causes the air to flow towards the ground, picking up moisture as it does so.

Plants also release water vapor into the air through a process known as transpiration. And because the air is more still at night, it’s harder for humidity to dissipate.

As a result, all of these factors combine to create higher humidity levels during the nighttime hours.

What Are the Different Levels of Humidity?

In meteorology, humidity is the amount of water vapor present in the air. Humidity indicates the likelihood for precipitation, dew, or fog to be present. The higher the humidity, the more water vapor is present in the air.

According to Science Direct, relative humidity is a ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature that ranges from 0% to 100%.

Absolute humidity counts the actual amount of water vapor present per unit volume of air and is measured in either grams per cubic meter or pounds per cubic foot.

Dew point temperature is another way to measure humidity, which is the temperature when water condenses out of air containing a given amount of water vapor.

The condensation happens when this temperature is reached or exceeded and results in either dew or frost forming on objects near the ground or other surfaces.

Vapor pressure is a function of temperature and it decreases as humidity increases. The term “saturation” means that relative humidity equals 100%.

When saturation occurs, condensation will happen and precipitation will occur if there is enough lifted condensation level (or LCL).

The formation of dew, frost, or rain happens when relative humidity reaches 100%.

There are tools that give readings that help us understand what the level of humidity is so we can better prepare for weather conditions.

Without knowing these levels, we wouldn’t be able to properly plan for things like concerts, outdoor events, agriculture purposes, etc.

Too much or too little moisture in the air can have negative impacts on not just humans but also animals and plants.

Levels of humidity also affect our everyday comfort as well as our health so it’s important that we know what they are.

How to Measure Humidity in Your Home

Accurate humidity readings are important for many reasons. They can help you determine if your home is too dry or too humid, both of which can be harmful to your health. They can also help you regulate the climate in your home to optimize comfort levels.

Fortunately, the humidity level in a home can be measured using a hygrometer. Hygrometers are very accurate and may be purchased at your local hardware or home improvement store.

A hygrometer measures the amount of water vapor in the air and comes in both digital and analog models.

By monitoring the moisture content of the air, a hygrometer can help to ensure that the indoor environment is comfortable and free from mold and mildew.

Additionally, a hygrometer can be used to monitor the progress of drying clothes or drying food. In general, a hygrometer is a useful tool for anyone who wants to maintain a comfortable, healthy indoor environment.

How to Reduce Humidity in Your Home

High humidity can cause problems for your health and your home, so it’s important to take steps to reduce the humidity in your home when necessary. Read on for tips on how to reduce humidity in your home.

  • Use a dehumidifier
  • Ventilate your home by opening windows and doors
  • Air dry your laundry outside
  • Cook with the exhaust fan on
  • Put moisture absorbers in your closets and cabinets

Taking steps to reduce the humidity in your home will not only make you feel more comfortable, you’ll reduce the risk of unwanted mold and mildew.

How to Sleep Better at Night with High Humidity

High humidity can be a real nuisance, particularly when it comes to trying to sleep at night. Not only does it make it feel much hotter than it actually is, but it can also lead to increased levels of condensation, which can make bedding and clothing feel damp and uncomfortable. Thankfully, there are a few things that you can do to help you sleep more comfortably on humid nights.

Invest in a Dehumidifier

Investing in a dehumidifier can be a game-changer when it comes to getting a good night’s sleep during periods of high humidity. Not only will it help to remove the excess moisture from the air, but it will also help to lower the temperature, creating a more comfortable sleeping environment.

A dehumidifier can also help to reduce the risk of mold and mildew growth, which can lead to respiratory problems.

Keeping the air dry will help to remove some of the moisture from the air, making it feel more comfortable.

Use a Fan

By circulating the air in the room, a fan can help to lower the temperature and make it easier to breathe. White noise produced by a fan can help to mask any outside noise, creating a more peaceful environment for sleep.

So if you’re struggling to get comfortable on a sticky summer night, try using a fan to see if it makes a difference. You just might find yourself sleeping better in no time.

Breathable Bedding

Make sure that your bedding is made from breathable materials such as cotton. This will help to wick away any moisture that does build up, making it easier for you to sleep through the night.

By following these simple tips, you should be able to get a good night’s sleep even on the most humid of nights.

FAQs About Humidity and Sleep

Have more questions? We answer a few below:

How does humidity affect sleep?

Many people find that high humidity levels make it difficult to sleep well. Humidity can cause condensation on windows and increase the amount of moisture in the air, which can lead to feelings of discomfort and difficulty breathing.

How to know if the humidity in your bedroom is too high?

The best way to determine whether the humidity level in your bedroom is too high is to use a hygrometer, which measures moisture content in the air.

What are some ways to adjust the humidity in your bedroom?

There are several ways to adjust the humidity level in your bedroom:

  • Use a dehumidifier: A dehumidifier removes moisture from the air, which can help to reduce humidity levels.
  • Open a window: Opening a window allows moisture to escape and can help to lower the humidity level in a room.
  • Increase ventilation: Increasing ventilation, such as by using an exhaust fan, can help to circulate fresh air and reduce the amount of moisture in the air.

Can humidity affect my health?

High levels of humidity can have a negative impact on your health. Humidity can cause respiratory problems, increase the likelihood of mold growth, and contribute to allergies and asthma symptoms.


High humidity levels at night can cause a variety of common sleep challenges, including discomfort, difficulty falling asleep, and respiratory problems.

However, there are several things you can do to reduce the amount of humidity in your home and get a better night’s sleep.


Trina Greenfield, Author
SmackDown Media LLC

About the Author:
Trina Greenfield, the owner of SmackDown Media LLC, is passionate about providing information to those interested in the air quality in and around their homes. Trina writes content about things she’s passionate about, such as safe, in-home air, educational platforms for children and adults, as well as all things family-related.