Past IEM Features tagged: humidity
Relative Humidity is one of the more commonly expressed weather variables. It represents the percentage capacity that the air is full of water vapor. Since the value is relative, it is difficult to directly compare the value at different air temperatures. While the air certainly feels drier in the winter time, the relative humidity values are just as high as the summer time. The featured chart presents a computed climatology of RH for Ames. The blue bars represent the daily range of RH values for each day this year. The blue, green, and black lines are simple averages of the daily min, avg, and max. The red line represents the frequency of days with the maximum RH at or above 95%. A lot going on with the chart! Of note for this time of year is that relative humidities are dropping. Demand for water and subsequent transpiration by agricultural crops is on the rapid decline. You may have noticed the corn and soybeans are turning brown now! These lower RH values help to dry out the fields and crops to allow for harvest.
Tags: rh humidity
The featured chart displays an analysis of water vapor surface mixing ratio values for Des Moines. This value is a measure of the amount of water in the air. It is not temperature dependent and can be simply averaged whereas dew point temperature can not. For all the rain and snow we have had, humidity levels have not been often to the extreme high end on a daily basis. Yesterday's levels were about average based on long term data at the site.
Yesterday was a very pleasant day with highs in the low 80s and comfortable humidities with dew points in the 50s. The featured chart presents the frequency of having a dew point temperature below 60 when the afternoon high temperature was above 80. You can see the frequency declines as we get deeper into summer and the humid air becomes unavoidable!
Tags: humidity summer