The Dewpoint 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. It is when the water in the air can no longer stay in its gaseous state and goes into a liquid state.
This is important for us to forecast weather, because if there is more moisture in the air, or if the dewpoint is equal to the air temperature, that can lead to clouds, rain, or snow. Dewpoint’s are also great for figuring out how comfortable we will be outside.
When Dewpoints are really low, in the single digits to the 20s, it means the air is very dry. When Dewpoints are this low, we tend to get chapped lips, or feel static shocks. This is because with dry air, electrons in the air cannot move around very well. Since they cannot move around, they build up on us or our clothes, leading us to be more susceptible to static shocks.
When Dewpoints are really high, in the 60s, that is when the air can feel very sticky and uncomfortable. This usually happens in the summer.