It's Hot, By Why is It Not Humid? There's Pros and Cons to Both |

The heat has arrived with temperatures expected to stay around 90 degrees through next week. Living in a dry climate that is not very humid has its pros and cons. It’s good that we don’t have to deal with the added heat during a hot summer, but bad in that it creates a more volatile environment for fires. Some parts of the country are so humid that your glasses can fog up when you go outside. That would be very rare in our area.

Well you may have heard the term relative humidity it does not give the full description for how much moisture is in the air or how sticky it is. Well relative humidity can show you how easy it is for clouds to form, the value alone does not tell you how much moisture is in the air. A water bottle is a good example of this. You can have two different water bottles one taller than the other with the same relative humidity. While both of them may be 90 percent full, the taller or warmer one would have more moisture.

The dewpoint is a better value for describing how humid it is outside and how much moisture is in the air. For reference, our dewpoints rarely get out of the 50’s, but Florida has dewpoints in the 70’s all throughout the summer months. The dewpoint tells you the temperature the air has to get cool to in order for saturation to occur. The higher the value, the more moisture there is to work with.

The heat index is figured by combining the temperature and the relative humidity. When the temperature is 96 degrees and the relative humidity is 45 percent it feels like 104.

A high relative humidity means the air is very saturated and evaporation will be tough to come by. When you go swimming and you get out of the pool, the heat evaporates the water droplets on your skin and cools you off. If you live in a humid environment, the water droplets would have a harder time evaporating and you would have a hard time cooling off. This is why low temperatures are usually warmer in the southeast than in the desert southwest.

Red Flag Warnings are issued when winds are strong, the relative humidity is low, and vegetation is dry. The relative humidity is used in this case because it tells us how likely it is to have rain. When the relative humidity is above 70 percent, rain chances are pretty high. When the relative humidity is low grass dries out very quickly because of evaporation and rain is less likely.