It’s been a sweltering start to summer so far, in part due to the humidity, and North Texans learned to embrace the phrase “air you can wear” this weekend.
The dew point approached 80 degrees Friday, which is a record high for the area. According to the National Weather Service, this record has been set five times since 1947.
Related: The dew point in Dallas-Fort Worth on Thursday reached record levels. Here’s why it’s so catchy
Over the weekend, humidity levels remained oppressive, staying in the low to mid 70s. Overnight, dew point values rose significantly due to cooler air, explained NWS meteorologist Monique Sellers.
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“Essentially, it’s mixing with drier air, so it’s going down throughout the day,” Sellers said, adding that the dew point climbed as high as 77 degrees Saturday and Sunday night.
However, the term dew point is often misinterpreted as a similar metric to temperature, since both are measured in degrees Fahrenheit, Sellers said. The reality is that they serve different purposes and report on different things in the environment.
In short, the dew point is the point at which the air forms dew, or tiny droplets of water that contribute to a sticky, unpleasant feeling outside.
In other words, the dew point tells us the temperature to which the air needs to be cooled to reach 100 percent relative humidity, or when dew forms, Sellers said.
“If the dew point is 80, it doesn’t take long to cool it down before you start to see moisture develop,” he said.
By itself, dew point doesn’t mean much. But combined with the temperatures, it’s often a good indicator of how it will feel outside. When temperatures are close to dew point, water vapor begins to develop, Sellers explained.
“When you start getting your dew point closer to your temperature, that’s when you start seeing things like fog and mist and things like that,” he said.
Also, dew point differs from humidity in that it measures the amount of moisture in the air, regardless of what the temperature is.
On the other hand, relative humidity is based on temperature, and tends to rise at night. When it’s cooler outside, it will feel more humid, Sellers said.
If you’re looking for moisture relief, don’t hold your breath.
The forecast for the rest of the week is about the same, at least in terms of dew point, and it’s expected to stay in the mid-70s through this weekend.
“It takes some kind of action, like maybe some drier air coming in, to bring those dew values back down,” Sellers said. But dry air, which can come from a cold front or a dry line, is hard to come by in the summer months, and especially so in Texas.
However, temperatures are forecast to drop a bit, which could provide some reassurance for North Texans.
“It can feel a little less hot, which lowers the heat index, which makes it a little less stressful to be out in the heat,” Sellers said.
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