The Dewpoint: explained


The temperatures are heating up across Michiana, and the humidity is coming with it. This time of year we start checking on the dew point temperatures to know if it is going to feel hotter than the thermometer shows.

With dew point temperatures in the 40s, the air is very dry and is able to evaporate our sweat. Evaporation is a cooling process, so it helps cool us down and moderate our body temperature. The higher the dewpoint is into the 60s and 70s, the more saturated the air is, and our sweat will not evaporate. This keeps our body temperatures high, and makes it feel hotter outside.

The “feels like” temperature that factors in the humidity is called the Heat Index

Dewpoints are also a good indicator of where thunderstorms will develop. For a thunderstorm to develop, there needs to be three things: instability, lift and moisture. The dewpoint shows us the moisture content of the air.

The dewpoint at ground level has to be at least 55 degrees for a thunderstorm to form. This means that there is sufficient moisture in the air. If dew point temperatures climb into the 60s and 70s, the air is even more moist, and severe thunderstorms become more likely. The reason for this is because moist air is less dense than dry air at the same temperature. Therefore, the moist air will start rising, and rising air creates storms.

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