The featured image presents an hourly climatology of the frequency of having a relative humidity observation below 60 percent. Since relative humidity is a function of temperature, as the air warms during the daytime the rh value will drop. The plot indicates two maximum in the late springtime and fall. These times of year have strong heating and less profilic sources of evapotranspiration. July into August are a time of maximum corn and soy plant transpiration which helps to keep relative humidity values even while temperatures warm.

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Bad = 4

Tags:   climate   rh  

The fun never stops with these hourly climatology plots. Today's feature is a simple hourly climatology of the average relative humidity observed at Des Moines. This plot shows a strong annual and diurnal signal! While dew point temperature is not a function of air temperature, relative humidity is! While the atmosphere cools during the night, relative humidities rise (air temperature drops, dew point remains nearly constant). This plot also shows the least humid time of year being in April, when temperatures are warming nicely and vegetation is not transpiring yet.

Voting:
Good = 29
Bad = 10

Tags:   climate   rh