I have been incorrectly calcuating the Whind Speed and Direction Averages since I began collecting data in 1999.
These data have now been corrected.
Averaging the direction in Access using the built in functions cannot be correct. If you have wind at 350 and wind at 10 degrees the average is NOT 180 degrees.
I have used the Vector system formulae from a Canadian Site which I found most informative.
Here is the structure of the calculations for averaging Wind Speed and Direction: From the sequence of N observations of wind direction i and wind speed ui, the mean east-west, Ve, and north-south, Vn, components of the wind are:
The resultant mean wind speed and direction are:
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