[Bart B.]

Kraig's right about reading mirage or heat waves. Focus your scope about 2/3rds the distance to the target and you can see the heat waves wrinkling across the field of view. Dwyer makes good, inexpensive wind meters.

Wind at the firing point has much more effect on drift than wind close to the target. As the bullet gets closer to the target, it moves more sideways per yard of downrange travel due to its ever decreasing speed.

Kraig, half of your effective clock values are not quite right. 11, 1, 5 and 7 o'clock winds are correct as you state and exactly half value or 50%; equal of the sine of the 30 degree angle which is .5. But at 10, 2, 4 and 8 o'clock, they're about 90% (exactly .866 ir 86.6% to be exact) the sine of 60 degrees. And at 45 degree angles to the line of sight at 10:30, 1:30, 4:30 and 7:30, they're worth about 3/4ths full value; 70.7% (.707's the sine of 45 degrees).

Note also that wind speed at different heights above ground ain't the same. Depending on the terrain and ground cover, winds 15 feet above ground can be near twice as fast as they are 1 foot above ground. And a .308 Win. bullet's no more than 3 feet above the line of sight for a 600 yard zero; 2 feet for a .300 Win Mag. Thanks to Kraig for pointing this out to me not too long ago. I knew there was a difference but not as much as I found out after a bit of reasearch on the subject.