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Hi, I'm Dave Thurlow for the Weather Notebook. We get many weather questions on the show from listeners like you.

Paul Macareas from Winchester, VA wrote in a question about temperature and humidity. "I've been told that they cannot in total exceed about 160. Meaning if the temperature's 80 degrees, humidity can also be 80 percent and the total would be 160. I'd like a little clarification on that please."

Is it true that the temperature, added to the humidity, can not exceed 160? If you're using a percentage for relative humidity - meaning a number from one to one hundred, no. For example, if it's 80 degrees with 100 percent relative that equals 180. That's more than 160. These conditions can be unbearable, but not unheard of. If you use a more precise measurement of humidity, the dew point, you have better rule of thumb.

You see dew point temperature is a measure of the moisture in the air. The higher it is the more humid it is. It hardly ever rises above 75 to 80. When the dew point does soar, temperatures rarely rise above 80 to 85. When air is that soggy it has to come from a soggy place. One example is the Gulf of Mexico where the water at its warmest is 80 to 85.

The hottest places in the world are deserts. They're typically around 120 degrees. Deserts are dry because their dew points are low, averaging around 40 degrees. Whether it's 80 plus 80 in Louisiana or 120 plus 40 in Arizona, the temperature plus the dew point rarely exceeds 160.

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