Dick Fultz runs the Cross Country Ski Shop in Grayling, MI
First off there is room for individual preference when it comes to pole length. So if you like your pole length don't let someone tell you it is too short or too long. In general stronger fast skiers might like a pole a centimeter or two longer and the same for when skiing a flat course. When skiing a hilly course a shorter pole would be easier and more efficient.
CLASSIC RACE RECOMMENDED POLE LENGTH:
81%-84% of Body Height
With your arm down to your side the pole should be mid way between your arm pit and the top of your shoulder. Since this technique has both the diagonal stride and the double pole/double pole kick it would be nice to have two different length poles. If you just double poled it would be nice to have longer poles but they would feel awkward and throw your form off when doing the diagonal stride.
SKATING SKIING RECOMMENDED POLE LENGTH:
88%-90% of Body Height
When standing in your shoes or boots and looking straight ahead the top of a pole should come between your chin and upper lip - just a recommendation. Basically when skating in the proper form (ankles flexed etc.) you don't want to feel like you are having to raise your hand too high to plant the pole in the proper place. It is a feel. If you don't have the feel ski more and you will get it.
CASUAL CLASSIC TOUR RECOMMENDED POLE LENGTH:
80%-82% of Body Height
A little shorter pole is easier to use. You don't have to lift your hands so high to plant the pole. When casually skiing classic style, one has a tendency to ski a little more erect which causes the hand and arm to drop a little - thus a shorter pole
Here is the SWIX RACING CHART (Pole Length is in cm.)
SKIER HEIGHT...CLASSIC LENGTH...SKATE LENGTH
4'11"...............120........................130
45'0"...............122.5.....................132.5
5'1".................125........................135
5'2".................127.5.....................137.5
5'3".................130........................140
5'4".................132.5.....................142.5
5'5".................135........................145
5'6".................137.5.....................147.5
5'7".................140........................150
5'8".................142.5.....................152.5
5'9".................145........................155
5'10"...............147.5.....................157.5
5'11"...............150........................160
6'0".................152.5.....................162.5
6'1".................155........................165
6'2".................157.5.....................167.5
6'3".................160........................170
6'4".................162.5.....................172.5
6'5".................165........................175
6'6".................170