Value returned by GetWindSpeed is incorrect
In the vanilla engine, the function GetWindSpeed produces a value between 0.01 and 3.0 inclusive every time it is used. The upper bound of 3.0 is only an educated guess based on personally observing numerous GetWindSpeed results. The current weather affects the resulting value: "it returns values, 0 indoors and floats outdoors (varying quickly, in overcast weather the values seemed to oscillate around 2)" - Morrowind Scripting for Dummies 9.0.
In OpenMW (0.44 RC), GetWindSpeed appears to produce the same result until the weather changes, with the four possible values being 0, 0.1, 0.2 and 0.5 (the only ones I encountered in my testing across different cells and regions). The results shouldn't be the same if GetWindSpeed is called numerous times in a row and a value of "0" should be reserved for interior cells.
Although GetWindSpeed is never actually used in a vanilla script, it appears to have a use in determining whether the player is in an "interior acting as exterior" cell. I unfortunately don't know of any mods that use it.
(RM-4449 from redmine: created on 2018-06-10 by Texafornian MW, )