Ask 2: What is the lowest humidity ever recorded in Houston?

KPRC 2 Meteorologist Justin Stapleton tackles your questions


At KPRC 2, we’re dedicated to keeping Houstonians informed. As part of our new Ask 2 series, the newsroom will answer your questions about all things Houston.

The question: What is the lowest humidity ever recorded in Houston?

The answer: This question is something we get in the weather office from time to time so let’s break down the issue.

The agency that tracks weather extremes is the National Weather Service. For here in Houston, the KPRC 2 Weather Team works with our local forecast office, NWS Houston, where they track the daily weather, including days of extreme weather and sometimes temperature.

Let’s start with a little background on what humidity is: Humidity is a measurement of the amount of water vapor in the air. Think of it as the “sticky" factor that you feel in the air, especially in the summer in hot and humid Houston.

The higher the humidity, the more moisture that is in the air, the “swampier” it feels when you’re out in it. This is why we show the heat index on the weathercasts. The more water in the air, the hotter it feels and can become dangerous leading to conditions like heat exhaustion or even a deadly heat stroke.

Now, let’s flip that equation: The less water vapor in the air, the drier that air is and feels. If you have ever traveled out to the desert southwest in the United States, this is a way of life. Humidity levels generally remain very dry, with the moisture content of the air usually less than 25%. That is why if you’re traveling through let’s say, Arizona, you may feel like you always need to be drinking water, or if your lips are chapped, it is because the air remains very dry.

Generally, that isn’t something we deal with here in Houston, given how close we are to the Gulf of Mexico which is generally the source of warm, moist air that dominates our weather pattern most of the year. However, there are times when we are able to tap into a very dry air, generally from a passage of a cold front and a strong, dry, and sometimes cold high pressure center that moves in and removes a good chunk of the water vapor in our air.

Now to the unfortunate news: We did some digging with help from our friends from the National Weather Service, but unfortunately, they don’t keep records for things like humidity, usually, just for extremes with temperature, rainfall, and severe weather events. However, if I were to wager a guess, the lowest ever would be either sometime in possibly spring time when we have had a storm pass and a strong, dry wind is moving through, or also potentially in that ridiculously hot summer of 2011 when we were so dry that temperatures spiked from 107 to 109 on August 27th through the 31st.

Relative Humidity Guide
Relative Humidity Guide

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