The wind speed in MPH above the line is for straight on, or straight against scenarios. The % of adjustment below the line corresponds to the number directly above it, to either be added or subtracted as needed. Diagonal winds need a bit of imagination and experimentation. For example a 9 o'clock to 3 o'clock breeze (or visa versa) needs no additional yardage added if your plan is to ride the full effect of the wind and DING your shot. This is an easy approach that works well for me. Of coarse various irons and ball combinations play a factor, as well as elevation and green speed. With my current equipment full backspin or topspin equals an additional loss or gain of approx. 4%, which can further be used to fine tune your shot.
5 7 10 12 15 17 20 (MPH)
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2 3 4 5 6 7 8 (% of adjustment )
150 yard w/ 17 MPH headwind ( 150 + 7% = 160.5 )
150 yard w/ 17 MPH tailwind ( 150 - 7% = 139.5 )