Here it is only June, and we are already seeing July and August like dewpoints. The dewpoint here in Sector Ocho is 79.2 degrees F, as recorded by my weather station and substantiated by another online personal weather station less than a mile away. Dewpoints above 80 degrees F can be fatal for people with breathing problems like Asthma or COPD. I was just outside, filling my truck with fuel, and it was so humid that it was difficult to breathe. With a dewpoint of 79.2 and an actual temperature of 92 degrees, the Relative Humidity is 66.4%, and the Heat Index is 109 degF. This is the part of the year that Florida residents like to refer to as “fuckin’ hot,” except it has arrived a month early. It’s 80 degrees at sunrise, for crying out loud.
The dew point temperature is the temperature at which the air can no longer hold all of its water vapor, and some of the water vapor must condense into liquid water. At 100% relative humidity, the dew point temperature and the air temperature are the same, and clouds or fog can begin to form. While relative humidity is a relative measure of how humid it is, the dew point temperature is an absolute measure of how much water vapor is in the air (how humid it is). In very warm, humid conditions, the dew point temperature can reach 75 to 77 degrees F, but rarely exceeds 80 degrees. The highest Dewpoint ever recorded was 95 degF in Saudi Arabia. The highest ever recorded in the USA was 88 degF in Moorehead, MN. There was once a dewpoint in Melbourne, Florida of 91 degF, but the station that recorded it was not an official one, so it didn’t count.
Dew point is the best indicator of comfort in a hot climate. Once the dew point of the air exceeds 66 degrees Fahrenheit or so, the air begins to feel hot and uncomfortably stuffy. The reason for this, is that your perspiration can not evaporate to cool you off.
Last week I was in Las Vegas. The temperature there was 115 degrees, but the humidity was only 6 percent, which calculates to a 108 degree heat index. I agree. It felt warm in Vegas, like standing in front of an open oven. It doesn’t feel as warm here, but it does feel more oppressive. The air feels thick and sticky.
I hope we get a bit of relief soon, or else I won’t be able to do anything outside until October.
joe · June 21, 2021 at 7:00 pm
just like tx…you know when it’s 80+ before sunrise, it’s going to be a bad day…
AC47spooky · June 22, 2021 at 8:18 am
We were outside working in the yard Saturday and it was brutal. You’re right — it’s a month (or more) early. As we age, it’s increasingly difficult to tolerate the high dew points. I noticed NWS said dew point was 77º the other night.
D.C. · June 22, 2021 at 9:05 am
Wow great science lecture! Great bit of knowledge base.
I imagine it applies to the weather inverse of cold and frozen precipitation too?
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