It’s the Humidity

It’s in the air we breathe, but what do you know about humidity?

You hear it all the time, most often in idle airport conversations. “It’s not the heat down there on the Gulf Coast that’ll get you, ” they say. “It’s the humidity.” But does this observation hold water (pun very much intended), or is it nothing more than a line from some universally known script of small talk?

Believe it or not, that airport stranger might be on to something. Upon closer examination, it becomes abundantly clear that humidity has helped shape much of our identity in the Port City, from the clothes we wear to the architecture we employ. But what exactly is humidity, and why does it insist on sticking around? Take a deep breath of that wonderful saturated air — we’ve got you covered.

Humidity is defined as the amount of water molecules present in the air. The word “humid” is derived from the Latin “umere, ” meaning, “to be moist.”

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Aside from the respiratory effects of humidity, moisture in the air also interferes with the human body’s ability to regulate its own temperature. When we get hot, our bodies sweat to cool down. In a dry environment, that sweat evaporates quickly, but in high humidity, sweat doesn’t evaporate as fast. As a result, we sweat more, which leads to dehydration and overheating.

Ever wonder how the Weather Channel arrives at that “relative humidity” percentage? Depending on the outside temperature, air can hold only so much moisture at any given time. Relative humidity, therefore, is a comparison of the amount of moisture in the air versus the amount of moisture the air could hold. A relative humidity of 50 – 60 percent is considered ideal. Dew appears on your lawn when relative humidity is 100 percent.

When the air is crowded with water molecules, odors are more readily transmitted through the air and to your nose. This explains why we are all so familiar with the smell of a wet dog. As water molecules evaporate from doggy fur, they carry the smell of bacteria into our noses — and living rooms.

When the air is humid, hydrogen bonds form between water molecules and the proteins that make up human hair, causing the hair to curl. In fact, human hair is so sensitive to moisture that it was used in 18th century humidity measuring devices.

A Humid History

  • “There is a kind of clammy, misty, calm heat here in the South, which already begins to be felt early in March, ” wrote English Captain John W. Oldmixon of his visit to Mobile in 1855. “One gasps for breath, and I look with wistful eyes down the street to the waterside and the shipping.” Trust me, John: We know the feeling.
  • Humidity even played a role in the development of Mobile’s antebellum architecture, particularly in relation to cast iron. “Due to the Port City’s notoriously humid conditions, ” writes MB contributor Tom McGehee, “cast iron as an architectural element soon replaced rotting wooden porches or was added to older buildings to make them more fashionable.”
  • “The source of our water vapor in Mobile is the Gulf of Mexico, ” explains local meteorologist Bill Williams. “Sometimes that vapor will get carried all the way up to New England, and they don’t like it. They call it a heat wave up there.”
  • Sure, you wear seersucker today because your mama dressed you in it before you could walk, but there’s another reason for the fabric’s popularity down here. In addition to being light, the fabric is woven in such a way that it bunches together, creating wrinkles that keep it off the wearer’s skin. This creates some much-needed air circulation throughout your dapper outfit, which helps combat the stuffiness of humidity. So now you see that mama really does know best.
  • Because moisture levels in the air affect the elasticity of vocal cords, researchers have determined that humidity directly influenced language development across the world. For example, more tonal languages, such as Chinese and Vietnamese, rarely developed in low-humidity climates.

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