SIOUX FALLS, S.D. (KELO) — It’s been a far easier summer so far both in terms of heat and humidity compared to last year. That will likely change by the end of the week.
As we get into the dog days of summer, those hazy, hot, and muggy days of midsummer will begin to become more prevalent. As they do, there’s some vocabulary you’ll want to know.
Relative humidity is how we measure the saturation level of the atmosphere at an arbitrary temperature. The dew point is the temperature that the air needs to be cooled down to in order for 100% saturation to occur.
Basically, the higher the dew point…the higher the moisture content in the air and vice versa. Something I like to use to illustrate this is the “glass half-full” analogy, where we compare the atmosphere to a glass of water.
Cooler air temperatures can be seen as a smaller glass of water, which won’t need as much to fill halfway. For example, in order to reach 50% relative humidity when the air temperature is 50 degrees, the dew point temperature would be just 32 degrees. If we increase the air temperature to 70 degrees, then we’d need the dew point to reach 51 degrees for the glass to be half full. For a 90-degree “glass” to be half full, the dew point would be nearly 70 degrees.
All three examples had 50% humidity, but the comfort level was vastly different between them. Simply put, more water in the glass means less comfort for us…and hot temperatures need a lot of water to simply be half full.
Keep this in mind later this week, as dew points reach the upper 60s and into the 70s at times with air temperatures well into the 90s.
