This is a summary method for
# S4 method for cfWind summary(object, calm_wind = 0)
a single number containing the wind speed that is considered calm.
A dataframe is returned containing the percentage of calm days
(wind speed >=
calm_days), percentage of variable days (wind speed =
990), and quantiles from the empirical cumulative distribution functions for
each CliFlo station at which there is wind data.