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Butler County,Iowa | Well, dew point temp = the temp u must cool the air to in order to condense water from vapor... If it doesn't get cool enough overnight, therefore, not much dew. So, even tho it seems you should get dew, it simply may not have gotten cold enough. See the pic below - from last night, overnight low happens around sunrise & it is higher than the dew pt reading at the same times. The dew point decreases with air temp overnight.
Along with that then, warmer air can "hold" more water. Rel humidity is the amount of moisture in the air compared to how much the air can "hold." Therefore, we can have a rel high dew pt temp with lower actual humidity due to high air temps. Side note tho, during the day, evapotranspiration from corn can SIGNIFICANTLY increase dew point temps in close vicinity to the fields. Since we r in Iowa, corn is everywhere.
Low humidity can be drying... This is most evident in the winter when humidities dip very low & we battle dry skin as a result. So, long story short, there are a lot of factors as you can see, but I would guess your observation of little dew is simply because air temp didn't quite get cold enough to reach dew pt. overnight. | |
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Evaporation map?
