Everyone knows Missouri is incredibly humid, especially in the summer. If you have a humidifier installed in your home, or are thinking about getting one, you might be curious if the system should continue to run during the already humid summer. Before we get to the answer, it’s important to understand what humidity is, how Missouri’s climate works, and how humidity impacts people.

Missouri is considered a humid subtropical climate under the Koppen climate classification. This means we experience hot and humid summers with cool to mild winters. Additionally, Missouri is an inland state without mountains or oceans to moderate the temperature. With these things in mind, you can expect to see the temperature fluctuate 100 degrees each calendar year.

In short, humidity is the amount of moisture in the air. Humidity and the entire system of determining the amount of moisture in the air and the effects on people is based on the principles of absolute humidity, relative humidity, dew point and heat index.

Absolute Humidity:

Absolute humidity is the mass of water vapor divided by the mass of dry air. For most people, absolute humidity isn’t a meaningful piece of data where they understand how comfortable they’ll be that day. However, it’s important for calculating things like relative humidity and dew point.

Relative Humidity:

Relative humidity is the ratio of absolute humidity to the highest possible absolute humidity based on air temperature. This basically says: of how humid it could be today, how humid is it actually? The closer relative humidity gets to 100%, the higher chance of rain.

Dew Point:

Dew point has to do with what temperature drops of dew/condensation can form. When it feels really groggy outside, it’s because the dewpoint and temperature are close together.

Heat Index:

The heat index is the metric most of us are used to seeing. This is the statistic that appears when you see “the temperature is 86 but it feels like 93.” It’s a combination of temperature and dew point, and gives people a reference to hot hot or cool the day will feel to them.

To maximize the impact of your home humidifier, reduce use or turn it off during the peak of summer (July-August). The reason MIssouri becomes so humid in the summer is because hotter air holds more water, and Missouri (unlike the desert) has enough moisture for a regular cycle of evaporation, condensation and rain.

Humans are sensitive to humidity. This is because we rely on the air to help regulate our body temperature through evaporation of sweat. When it becomes too humid, sweat is unable to evaporate. With all of this extra moisture hanging on us, we feel hotter and uncomfortable. For this reason, we recommend lower your humidifier or shutting it off during the hottest months of summer.

While humidifiers can cause more harm than help during summer, they’re crucial for a comfortable winter. Just as too much moisture in the air can negatively impact people, too little moisture can produce the same effect. Without adequate moisture in the air, we’ll experience dryness in our eyes, nose, throat and skin. This leads to itchy skin, overproduction of mucus and, occasionally, bloody noses.