What is the "dew point" (or dew point temperature)?
The dew point is also called the "dew temperature". This is simply the temperature in degrees below which dew settles naturally on the outside. Dew, are those little droplets of water that you find in the morning on the grass, for example, and they have an association with a certain humidity at dawn
To go into more detail, note that the dew point is a measure of the moisture (i.e. water vapour) content of the air (or any other gas). This condensation process is a well-known phenomenon in weather forecasting and the term "dew point" refers to the dew point’s temperature.
Let's move on to the technical side! Below the dew point temperature, condensation of water vapour in the air occurs. It condenses (i.e. liquefies) on surfaces due to air saturation. Indeed, the dew point temperature is a temperature which, once reached by air at constant pressure, becomes saturated with water.
The dew point temperature depends mainly on the temperature, the atmospheric pressure as well as the relative ambient humidity.
Right, but how is the dew point important to weather forecasting?
The first thing to know is that the dew point is not only used for morning dew. On the contrary, it is a subject that allows us to use this phenomenon as a reference, but it is more widely used to designate the fact that condensation deposits water vapour from the air or gas on a surface.
The Netatmo Smart Weather Station gives you all the information you need about the weather: from weather forecasts to wind speed, rainfall, temperature, indoor air quality, humidity, indoor air pollution, air quality… and of course the dew point!
How to measure the dew point according to temperature, atmospheric pressure, and humidity?
If you know the ambient temperature (thanks to a thermometer), the atmospheric pressure (in hPa available on certain measuring devices and from the weather service), and the relative humidity (thanks to a hygrometer), you can simply consult online measurement tables.
The dew point temperature is closely related to each of these variables, so you can get an accurate picture if you have no other way of finding out.
Some measuring instruments allow knowing at a glance the dew point temperature: such as the dew point mirror hygrometer and digital, connected, and intelligent weather stations. They can combine temperature, atmospheric pressure, and humidity to calculate the dew point.
No need to take different measurements and spend hours on complex measurements, these devices guarantee an accurate dew point measurement!
The dew point temperature is therefore an indicator of air humidity which is essentially based on 3 factors: ambient temperature, atmospheric pressure, and relative humidity. This is a measure that is mainly used by meteorologists but is equally useful for individuals. What are you going to do with the dew point?