When it comes to the human body, more water vapour in the air means that our cooling mechanism, sweating, becomes much less effective. This would make it seem like it wasn’t very sticky outside when it would be. Dew point is the temperature at which the air must cool in order for water that is currently present in the form of vapour to condense into a liquid. If the air temperature was 85 degrees, and a dew point of 65 degrees (humid air), which would indicate it being a more muggy day compared to a 20 degree day, the relative humidity would only read as 51.2%. This would lead you to believe it is sticky out, when it isn’t. This is expressed as a percentage, and also is why dew points are better to use to describe how the air makes us feel.įor example, a temperature of 20 degrees with a dew point of 20 degrees (dry air), will give you a relative humidity of 100%. RELATIVE HUMIDITY: Relative humidity is the measure of the amount of water vapor in the air currently, compared to the amount that can exist at the current air temperature. When Dewpoints are this low, we tend to get chapped lips, or feel static shocks. When the dew point temperature falls below freezing it is often. When Dewpoints are really low, in the single digits to the 20s, it means the air is very dry. If the dew point is high, the moisture content is also high at certain temperatures. When Dewpoints are really high, in the 60s, that is when the air can feel very sticky and uncomfortable. The lowest dew point reading has been 48.2 degrees fahrenheit at 3:50 PM, while the highest dew point is 57.2 degrees fahrenheit at 6:35 AM. Weather Chicago First Alert Weather: Chilly Saturday night, but warmup on the. The following chart displays hourly Saint Louis, MO dew points today (Sun, Jun 19th 2022). Dew point’s are also great for figuring out how comfortable we will be outside. Saint Louis, MO dew points today from 2:00 AM on Sun, Jun 19th 2022 until 10:00 PM.
This is important for us to forecast weather, because if there is more moisture in the air, or if the dew point is equal to the air temperature, that can lead to clouds, rain, or snow. It is when the water in the air can no longer stay in its gaseous state and goes into a liquid state. The dew point is measured as a temperature, while the relative humidity is expressed as a percentage.ĭEW POINT: The Dew point is the temperature to which air must be cooled for saturation to occur at a constant pressure. When the air temperature and the dew point are at the same number, or around the same number, that is when fog or precipitation will form. Dew points compared to relative humidity can be confusing, but they actually are two different things.