The Dew Point Is the Best Way to Measure Your Misery 
After walking outside and instantly sweating through my shirt a few days ago, I found myself in a very familiar position – hot, tired and uncomfortable. It was another summer day in New York City.
You know, the ones where the subway smells like a curious mixture of old Chinese food and body odor at 7:30 am. Where the ice in the $6.00 coffee you purchased from Starbucks 32 seconds ago already has already completely melted. One of those days.
The funny thing about that disgustingly humid morning is that when I went to check my phones weather app, it told me that the relative humidity was only 53%. That’s right, folks! Fifty-three percent. With a temperature of 88° F and a dew point of 69° F, miserable conditions under any circumstance, the relative humidity was only 53%.
Which leads us to our most important point: The dew point is the best way to measure your misery.
Dew point is an absolute measure of the amount of moisture in the atmosphere, while humidity is a relative measure of dew point as it relates to the temperature.
In more technical terms, the dew point is “The temperature where any air mass when cooled to that temperature reaches 100% humidity. It is expressed as measure of degrees.” Humidity, on the other hand is defined as “The ratio of water vapor in the air to the maximum amount of water vapor in the air that could be present if the air were completely saturated at a given temperature.”
By nature, the dew point is a better measure of how humid it feels outside because it is not relative to anything else. It is absolute, direct and stands alone as the single best measure for how miserable you’re going to feel upon walking outdoors.
That’s why we created our realistic dew point chart. It gives us a way to measure how miserable we are going to be on a given day. The prime time dew points generally range from the upper 40’s to the 50’s, leading to maximum comfortability. Below 40 is generally too dry/chapstick weather and above 65 is when the instant-sweat conditions return.
Today, we’re expecting dew points to move solidly into the “instant sweat” level and perhaps even close to “hellscape” level – it’s disgusting out there. We should start to see some improvement by tonight and especially by early next week. September is notorious for bringing a handful of sunny, lower dew point days where New York City really shines.
With that in mind, forget about relative humidity and start checking the dew point before you head outside. You’ll be grateful that you did!
