This week’s Q&A is an excerpt from Dear Frank…Answers to 100 of Your Golf Equipment Questions
Frank,
I thoroughly enjoy your videos and answers on the net. My question is this – Whenever I am playing near the ocean, be it in New Jersey, South Carolina or Florida it seems that I am at about one club shorter than when I play in my home state of Pennsylvania.
Is this due to humidity, altitude or turf conditions?
– Art
Art,
If the air is dense, the ball will fly shorter than in less dense air because of the aerodynamic drag properties. As the density of the medium increases so does the resistance to going through it.
Dense air also increases the lift forces on a spinning ball so the ball will have a higher trajectory in more dense air. The density of the air increases when it is cold and when you change altitude from Denver, Colorado to the coast of South Carolina. Also as the humidity increases the air density will decrease not increase as we intuitively believe. The effect of humidity on ball flight is not nearly as significant as altitude or temperature.
You can add about 2.5 yards for every 10 degrees of temperature increase from 35 degrees F, to 95 degrees F. In temperatures outside of this range you should not be on the course at all so don’t worry about it.
I think also in your case Art, the turf may be playing a part in the decrease in distance you are experiencing. My advice when playing at the coast is to estimate your distance and take out an extra club for all your irons and enjoy your beer at the end of the round.
Frank
franklygolf 
The rule of thumb I learned playing in New Mexico 45 years ago is that one mile of altitude is a 10% change in distance. I play at 2,100 feet at home and played at Hilton Head this week (sea level). So I added 4 yards for every 100 yard shot. But since it was 93° and warmer than playing in the mountains, there was and adjustment the other way! For a 150 yard shot, it played about 5 yards long which is 1/2 a club difference.
The key feature I use my Sky Caddie for is to measure my shots early in the round to determine how far I am hitting the ball in the air and on the roll that day. Knowing my actual CARRY & ROLL distances on each shot hit, helps me determine what I should hit the next time I have that distance. Example, my 8-iron averages 104 yards in the air and a 12 yard roll for a total of 116 yards. If I need 108 yards to carry a bunker and 110 to reach the front edge of a green, I would hit my 7-iron, which I hit 114 in the air and 10-12 yards of roll because my 8-iron is going to leave me in the front bunker.
For a variety of reasons (temperature, air density, with the wind, against the wind, old age, etc.), I will not hit a ball the same distance as I had the day or two before my current round. That’s why my early current round readings on holes 1 & 2 help me determine my club selections for holes 3-18.
When I first bought my Sky Caddie, I immediately measured every wedge shot I took with my PW, SW and 60-degree. I was stunned to find my good 60-degree wedge shots carried 42 yards and rolled 3-8 yards after landing. I had been using it to hit CARRY 50 yards and was frequently ending up in bunkers short of the green. I learned that I can only hit the 60-degree when my Sky Caddie says 40 yards or less to the front edge.
Knowing your CARRY and ROLL distances on each club in your bag helps you make better club selection decisions on each shot you face.