I see on weather apps that for a given temperature and humidity, the dew point is x. I looked into it and I learned that the the dew point is the temperature that air must be cooled to in order for dew to form. I also saw that the formula for the dew point (Td) is Td = T-((100-RH)/5) there T is the observed temperature and RH is the relative humidity.
If this formula is accurate, then in my mind, it means that Td would be recalculated whenever T drops, thus making the dew point impossible to reach.
For example: T = 26 and RH = 60% then Td = 18. If the temperature then drops to 18, we have T = 18 and RH = 60%, so Td = 10, and so on, meaning that the dew point for a given moment is never reached…
Where am I going wrong?
In: 3
The dewpoint is a measure of absolute humidity. It is not directly dependent on the temperature. In the night, when the temperature falls, the dewpoint may stay the same, which is why when you wake up there may be dew on the grass. You have relative humidity of 100% when this happens… at least in the air right over the blades of grass.
I agree it’s a confusing scale.
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