Memories of the 28th Century

Recently, I became thoroughly sick of hearing about “wind chill” and “real feel” temperatures. I learned enough about meteorology years ago, so that I understood that the wind chill refers to “wet bulb” temperature, and the real feel is another term for talking about that. Wet bulb temperature is the temperature measured with a thermometer that is wrapped with a wet cloth, so that the cooling due to evaporation is measured, in addition to the ambient air temperature. Dry bulb temperature is the temperature measure with the wet wrap, so that only the actual air temperature.

In addition to evaporation, wet bulb temperature measures the greater conductance of the water, and it gives an indication of the general effect of water on temperatures. Remember that water in any state (solid, liquid, or gas) will absorb heat and hold the heat for some time. That happens regardless of where the water is or the source of the heat. In addition to that causing the atmosphere to warm, it causes people to feel warmer or colder when the atmosphere has a higher concentration of water. Since the water will absorb heat from warmer things, people usually will fell chilled when the air is humid at a lower temperature. For example, if there is fog and the temperature is forty degrees Fahrenheit, the dampness will fell cold. And the opposite situation will also happen: if it is ninety-five degrees and humid, it will feel warmer, because the body can't transfer heat to the air.

The wind chill is based on the cooling of a wet bulb, but few people are wet bulbs. If you were to go out in soaking wet pajamas, when the temperature was thirty degrees and there was a thirty mile an hour wind, then you would feel very cold. But if you went out in soaking wet pajamas, then you would deserve to be chastised in some appropriate way, and freezing would be suitable. But remember that you would feel cold, because the wind would be evaporating the water in your pajamas, and the water would be conducting the heat from you faster, than if you were dry, and there would be relatively more heat in the air; this works only up the point where your body can’t transfer heat into the air. Above that point, it will feel hotter, and the humidity will make it even worse. People can become accustomed to almost anything, even high temperatures and humidity.

The actual facts of perceived heat or cold level relative to atmospheric moisture are not important to TV meteorologists. They are entertainers whose responsibility is to keep viewers watching so that they will see the commercials. People who know what to pay attention to get some of that information, but wind chill is not one of those things. Temperature, wind direction, and potential future weather systems are worth knowing about, and they are usually provided, but it would be very nice to know the position of the jet stream, because that pushes weather, and it is almost impossible to predict weather without knowing about the jet stream, and that may be why TV meteorologists don't show that. With the Jetstream there would be little reason to watch the meteorologist for a few days, because we would know what would be coming up next.

But if you want to enjoy wind chill, then put on your pajamas and take a cold shower before you go outside and dance in the ten degree wind.