As I wrote about the actual fitting part of fitting a golf ball last week, it got my mind working.  Wheels were turning.  One of the things I hate is when we (you or I) go through a great fitting with a player over the winter.  The player is so excited to get his new clubs.  He waits and waits like a kid on Christmas morning.  We do a rush to get them out the door and to him in time for his trip to Florida.  They make it – just in time.  PHEW!!  He’s pumped!!  Out with the old, in with the new.  2 weeks later he comes back home.  You see him and say “Hey Doc, how did the new sticks work out?” “Actually, not good.  They don’t go anywhere.”  Any answer you give here is going to sound like an excuse, so the better part of reason is to head this off at the pass.  Address this upfront and make him aware of what I’m going to tell you.

As a good player, you know that playing golf in different conditions will change how the golf ball flies.  Rain, humidity, wind, elevation, temperature ALL impact a golf shot – most of it negatively.  In fact, the only one of these that won’t negatively impact a shot is humidity.  Trackman has a Normalization function, which essentially rules out ALL external factors.  It assumes a Tour quality golf ball at 400 feet of elevation (adjustable, but I use 400 feet), 70 degrees and no wind.  Essentially, how would this ball fly under perfect conditions?  This essentially tells us what is the best result that shot could have given us IF we had a good ball (not a range ball), or it wasn’t 55 degrees out, or it wasn’t into the wind, etc. – if we didn’t have the bag full of excuses.  Haha.  Funny how when I go to an event that is in the Adirondacks on a nice downwind day and I normalize, the ball will actually show a shorter distance.

So, how do external factors contribute to ball flight?  Keep in mind that a ball will be traveling it’s fastest immediately after impact, and that doesn’t change if you’re in Miami (sea level), in Denver (mile high), or on Mount Everest.  What happens after that is very different.

Elevation 

It has long been said that higher altitudes make the ball fly further either due to reduced gravity or thinner air.  Pro tip: it’s not gravity.  Gravity is reduced on top of Mt Everest by about .25%.  There are greater fluctuations in being further North or South in the US than up or down a mountain, but neither amounts to anything of consequence.  Air density, on the other hand, makes a difference.  Air is less dense at higher elevation.  A golf ball has an easier time traveling through air that is less dense (thinner).  As such, it doesn’t slow down as quickly, which means it will carry further.  At 5,000 feet, for example, the ball will fly about 6% further.  A 250 yard tee shot in Miami will fly 265 in Denver, all other things being equal.  Conversely, the difference between say Syracuse (roughly 400 feet) vs. Miami (sea level) will be about .5% – or about a yard and a quarter on out 250 yard tee shot.  

Spin rate does not change at elevation. However, the thinner the air, the harder it is to get lift at impact, which means the shot will have a flatter trajectory which will make the ball land flatter which won’t allow it to stop as quickly – despite the same spin.  So it will SEEM like it has less spin, but it doesn’t.  Side spin, however is reduced at Altitude.  At 5000 feet, the air is roughly 14% less dense, so that means the lifting force is 14% less.  That reduced lifting force will also make the shot curve 14% less.  Likewise, the ball will curve a little more in more dense (colder) air.

Temperature

It’s probably not as big of a deal as you think. I used to say it’s a full club per 10 degrees under 70 degrees. It’s probably closer to a half club per 10 degrees under 50-55 degrees – call it 5% per 10 degrees. The difference between 60 degrees and 90 degrees is negligible to a golf ball. If it’s 100 degrees, you may get a little extra. If it’s 40 degrees, you may loose a club. HOWEVER, the ground will typically change, so you may experience more or less total distance due to roll out along with the temperature. As you’ll see below, elevation will also have an influence in trajectory, which can also influence roll out. Soft ground and 40 degrees can make a long day. 40 degrees would cost you 10%, so your 250 yard tee shot now goes 225. if 25 yards of that 250 is roll, and with a soft fairway, you don’t get any, it’s likely that that 250 yard shot might plug at 200.  

Worth noting is that a warm ball flies further than a cold one. The USGA wouldn’t put a rule in the rule book about artificially warming a ball if it didn’t make a difference. You can use your hands or your pockets (period). A good rule of thumb is to keep you ball in your pocket as much as you can when it’s cold. 

Humidity 

Humid air feels wet and heavy, but it’s actually less dense than cold air. The ball will actually fly a little further in humid air than in cold dry air. The distance gained or lost is small, but it is worth noting that the trajectory will be different in humid air (less dense = easier to generate lift at launch = higher flight) than colder, more dense air (lower flatter flight). Convert this to Florida where you have high humidity, wind and low elevation. All of these things will make the ball fly shorter than an Upstate New Yorker may be used to. 

Wind

Wind has a dramatic affect on a golf ball.  We all know that.  Wind will not help as much straight downwind as it will hurt straight into a headwind.  A good rule of thumb is to add 1% for every Mile per Hour of wind in a headwind, and take away .5% for every MPH in a tailwind.  So, a 250 yard tee shot that is in a 10 MPH wind will add an additional 12.5 yards downwind, and reduce by 25 yards into the wind.  The age old advice of add a club for every 10 MPH of wind is still pretty sound.  Downwind?  Take away a half club for every 10 MPH.  We’ve all heard that would go XXX yards if it was down wind in Denver.  Your 250 yard tee shot in Syracuse would go 6% further due to the elevation and another 10% further in a 10 MPH tail wind – netting him 290.  Fun Fact: To break his chops, a normal 250 yard tee shot would need to be 14MPH downwind in Denver to go 300.   

Cross winds?  Ugh.  Any good player knows there’s an art to club selection in the wind.  A good rule of thumb is that the ball will fly further if it curves with the wind and shorter if it curves into the wind.  Most good players will try to work the ball into the wind because the distance control is easier to calculate. 

Rain

Rain falling from the sky will work against your ball.  Simply put, it’s harder for your ball to stay in the air with rain working against it.  The more rain in the air, the shorter it will go.  Normal rain will be about a 5% reduction across the board.  Rain makes the air more dense, which as we know from above, will also make the ball go shorter.    

As the shots become shorter, the effect is reduced.  The shorter the shot, the slower it’s moving, the less it’s affected.  English please?  Slower swing speeds are less impacted than faster swing speeds.

What’s the takeaway?

Say a player plays at Lakeshore Yacht & CC (elevation is 400′) and gets a reciprocal to go play the Pompey Club (elevation is 1500′).  The ball will go a couple yards further there.  It’s windy on top of the hill at Pompey.  The ball may go a club shorter on average. Point is, there can be a difference going from one club in Syracuse to another.  

Let’s say the same player now goes to Florida.  It’s hot, windy, at sea level and maybe a slight rain (hey, we’re here, we have to play).  Thicker air and lower elevation may take away a half club.  The wind could be another half club.  The rain?  Another half club. And, just because it’s 90 degrees, the ball isn’t going to travel any further.  Is it conceivable that your player that you fit and hits his 7 iron 165 in perfect conditions here in the Northeast, could hit it 150 -155 in Florida?  YES.  IN fact, it’s expected.  Perhaps a higher handicapper who doesn’t know his distances as well, and goes off his best ones may notice an even bigger disparity.  

Set the stage BEFORE he leaves.  Let him know that he WILL hit it shorter in Florida.  Let him know that a 150 yard 7 iron is the same as a 162 yard shot here, all other things being equal.  Drivers will go disproportionately shorter, and wedges will be less affected.  “But, I know my distances down there.”  Maybe so, but they are SHORTER than here, and any adverse condition, while it may not seem adverse to the player IS adverse to the golf ball.  New irons or not, they will go shorter.  In fact, if they go the same distance, you did a really nice job on that fitting!!! 

Hope this helps. Until next time – happy fitting!!