Boogie,
I don't think compiling an average would be particularly helpful.
If you want to complete a course in minimal amount of time, go somewhere the weather is typically good at the time of year you are doing your training. An "average" might not help you in this respect. For example, I had an absolute requirement to do my CPL in 3 weeks or less. I chose Florida because at the time of year I was doing my CPL, the weather suited my requirements. Had I done my CPL in hurricane season, Florida would have been a very bad choice for me.
Also, lots of people have requirements which are more important to them than the time it takes to complete the course. Examples would be quality of training, cost of training, ability to fit training around work or family commitments, and so on - but I'm sure there are others I've forgotten.
FFF
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