Prior to moving to Hawaii, I played golf in South Florida for nearly 50 years. I was fortunate to be able to travel frequently and I've played several round of golf in Colorado, as well as at other golf courses at altitudes over 5000 feet. What I observed when I played in Colorado was that I would have to hit one club less to attain the same yardage I do at sea level. Normally I hit my seven iron 155 yards with a good swing, but it would travel around 165 yards when I played courses a mile high or slightly higher. If your normal drive at sea level is around 245 yards, (which mine is), you can expect to consistently get 15-25 yards more on your drives. Of course several of the courses I played were 300-400 yards longer than the courses I played in South Florida. So the extra distance you get is usually negated by the longer golf course.