Humidity/Air Quality and distance.

[Chas]

Mitch,
Please provide hard data to support your personal impressions .....
[not that I've got any data myself of course]

Qualitatively (not quantitatively), the effects of temperature, humidity and altitude on air density and thus on ball flight are analogous, and so it would be very hard to reconcile opposing effects between any two as you seem to be suggesting. IOW, what is true for temperature would be expected to be true, mutas mutandis , for humidity as well.

Most golfers who've been at it for a few years (and have even travelled far from their home track ) have experienced a wide range of weather conditions, vis. hot, cold, dry, humid, windy, calm, etc etc. Admittedly some have more experience of searing, clammy conditions than others ......

Good grief, I spend time on this forum in part to escape threads like this in a certain excellent GA (general aviation) forum. Now I'm just waiting for someone to post a scenario like, "what if I were standing in the tee box on a conveyor belt that was travelling sideways at 50 knots (I mean m.p.h.) relative to the fairway, and the leading edge of a microburst hit me just as I was starting my down stroke .....".

* rubs forehead*

[David in FL]

I think in general that is true. But what about wet and low versus dry and low? All of my golf is played at about 400 ft above sea level and in my experience, the ball flies better when it is hot and dry than it does when it is hot and wet.

The difference in actual air density due to a change in relative humidity is so low that as a rule, pilots don't even consider it when calculating density altitude. That doesn't mean that it can't be calculated though, and as a pilot as well as something of a numbers weenie, I thought it might be fun and instructive to do so. Here's a a link to the calculator that I used...... http://wahiduddin.net/calc/calc_da_rh.htm As a test, I entered 2 different scenarios and measured the difference in density altitude as well as the difference in relative air density.... The first scenario was at your 400' above sea-level altitude, at standard air pressure of 29.92", 95*F, and 40% relative humidity. The density altitude in that scenario is 3,050', and the density of the air relative to ICAO standard conditions is 91.38%. The second scenario leaves everything the same except the relative humidity which is increased to an almost unbearable 95%. The density altitude rises to 3,447' and the relative air density drops to 90.3%. To summarize.......by changing from a scenario of little relative humidity to one of extremely high relative humidity, the density altitude only increased by 397' and the relative air density only dropped by about a point. Given the inefficiency of the small amount of lift generated by a golf ball in the first place, clearly the tiny change in relative air density due solely to an increase in relative humidity isn't going to cause such a significant change in the lift generated that it will offset the lessened drag associated with the same reduction in air density. Cool, huh?!

[Mitch C]

It was super-hot and super-humid at the PGA at Southern Hills, and all the players were talking about was how far the ball was going. There was your 95 degrees and up type of weather.

I've lived in Tulsa. Tulsa isn't humid. Tulsa gets moderately hot, but it doesn't get really humid. In fact, when it gets hot, it is almost never over 20 percent humidity.

As an aside, I played Southern Hills with a well heeled friend who had a junior membership. I lived right across the street from Southern Hills at 61st and Lewis. Tulsa doesn't have the kind of humidity I'm talking about. And the primary reason balls fly farther in heat above 95 degrees has more to do with the composition of the balls more than anything else. Personally, I don't think humidity or lift have all that much to do with ball flight. One source I read said that the lesser density of air because of humidity might add 18 inches to a drive. So, in reality, I think it is much ado about nothing. However, I'm here to tell you that the ball travels better in August when it is hot and dry than it does in June when it is hot and humid.

[iacas]

Good grief, I spend time on this forum in part to escape threads like this in a certain excellent GA (general aviation) forum. Now I'm just waiting for someone to post a scenario like, "what if I were standing in the tee box on a conveyor belt that was travelling sideways at 50 knots (I mean m.p.h.) relative to the fairway, and the leading edge of a microburst hit me just as I was starting my down stroke .....".

Ah, but did you see

this thread ?

[flopdarock]

im from hawaii... now i live in a really humid part of the east coast... besides sweating my butt off... i dont really notice a difference

[Saint]

Personally, I don't think humidity or lift have all that much to do with ball flight. One source I read said that the lesser density of air because of humidity might add 18 inches to a drive. So, in reality, I think it is much ado about nothing.

I'm with ya mitch. When I'm in clarendon or canyon, both just off the caprock, we get days that are 105+ degrees and the air is super super thin, due to there being no humidity. On days like this, you can add about 10 yards a drive more easy. So that gets me to thinking with the less humidity and more heat, maybe the ball compresses more, giving more of a trampoline effect, thus bigger drives.

[Chas]

we get days that are 105+ degrees and the air is super super thin, due to there being no humidity.

Oh dear.

I give up. But if a golf ball had sweat glands, it might be a different story. Thanks for the link Erik. Some very entertaining posts. I have a theory, which is that all internet forums are frequented by the same core group of people who just adopt different usernames and who don't really DO anything at all outside of their silicon playgrounds. I recognized a lot of those people in that conveyor belt thread of yours. And I must be one as well.

[Saint]

Oh dear.

well, come up here to this texas heat, and see to it yourself. And i'm not the only one that thinks so. when you go to the clubhouse and everyone is talking about how they are hitting it so far, it's odd.

[Chas]

I might take you up on that. But if I did I'd prolly do very badly because I don't play well when suffering from heat prostration. This definitely reduces my distance off the tee.

Answer me this and I might treat you to a round at TP (cart included): exactly why does an altimeter (which is really just a pressure gauge) measure LOWER when ambient air temperature is RAISED? The lower the pressure of surrounding air the higher an altimeter will indicate of course, so this altimeter error (resulting from temperature change during flight) is highly counter-intuitive. It took a professional pilot to final explain this one to me in a way that I could grasp. But to play Torrey gratis you have to figure it out all on your own, Scout's Honor. No Mulligans.

[Saint]

man, i have no idea what you just said. i hate with a passion chemistry. And yes, it sucks to play on a day that it is 103. Who knows, there could be a loop hole in all this science junk.

[Mitch C]

man, i have no idea what you just said. i hate with a passion chemistry. And yes, it sucks to play on a day that it is 103. Who knows, there could be a loop hole in all this science junk.

I am certain that the temperature of the balls and the way the cores react to heat has more to do with hitting it far on hot days than anything else. Once you get above 90, it really starts to take off.

I really don't think humidity has that much to do with it. I only made my post to point out that it might not be as clear cut as some were asserting. There are lift forces at work as well and it is possible that those are sometimes enough to counteract any increased density of the air and give longer ball flight. And really, it is kind of stupid to argue that the decreased drag of less dense air has an effect on the ball, but that the corresponding decrease in lift has a neglible effect. Drag and lift are just opposite sides of the same coin. But nevertheless, the ball does travel farther in August than June.

[David in FL]

Answer me this and I might treat you to a round at TP (cart included): exactly why does an altimeter (which is really just a pressure gauge) measure LOWER when ambient air temperature is RAISED?

Can I play? .......and I can answer it in 3 words, nah, make that 2 words.

[Yukari]

I might take you up on that. But if I did I'd prolly do very badly because I don't play well when suffering from heat prostration. This definitely reduces my distance off the tee.

At high temperature molecules move faster, and therefore the air molecules are further apart. Since smaller amount of air molecules occupy the same volume, the pressure is perceived to be lower.

Now when and where do I show up for the free round?

[wachesawgolfer]

That is interesting to me that humid air is less dense than dryer air, considering that a cubic foot of water is much heavier than a cubic foot of air and it is much harder to hit a golf ball through water than air. I learned something.

[Chas]

At high temperature molecules move faster, and therefore the air molecules are further apart. Since smaller amount of air molecules occupy the same volume, the pressure is perceived to be lower.

Damn but you're good.

What the heck do you fly btw (if you're a pilot), a Bo'? Out of KLGB? Nicely put, but personally I think of it in terms of a column of air from the ground to the outer limits of the atmosphere that expands with increasing temperature; as the column gets hotter the density distribution shifts upwards (away from sea level) and so air pressure at a given altitude (mean sea level of course) is actually HIGHER. A graph would show it much better I would think. You stated it in few words, bravo! FORTUNATELY, my offer was restricted to a poster by the name of Saint, who just disqualified himself in no uncertain way in his latest post. But that was very candid of him ..... What a terrible shame, and there I was all ready to show Saint the great majest and challenge of our own most famous and historic Torrey Pines South, lately home to the U.S. Open and forever dear to all SoCal golfers. * sigh * p.s. The Saint and I agree on one thing tho': it sucks to play when it's 103, and the more so the more humid the air is. This has more to do with Biology than with Physics or Chemistry however.

[Chas]

That is interesting to me that humid air is less dense than dryer air, considering that a cubic foot of water is much heavier than a cubic foot of air and it is much harder to hit a golf ball through water than air. I learned something.

And that is why it seems counter-intuitive. However, air is a mixture of molecules in the gaseous phase (oxygen, nitrogen, CO2, water, etc), and as Erik has pointed out the relative contributions of different molecules to air density is a function of their relative molecular weights. Water has 2 hydrogens (1 weight unit each) and only one "O" (=16) - compare the total with that of the other components of air yourself. Ergo, water vapor is relatively light!

One cannot draw conclusions about relative densities in the gaseous phase from relative densities in the liquid phase, which can be very different indeed. What determines the density of a liquid is a whole 'nother thing (gases are much simpler when it comes to this sort of thing). It would take a real chemist or physicist to explain that one properly - as a mere biochemist I've gone as far as I dare and prolly further than I should have.

[Saint]

well crap, i knew that, i thought it was going to be some hard drawn out answer, lol.

[Brendan Tummon]

i.ve been playing in thailand and i have seen my drives and irons  shots lose ten to twenty yards on them and its hot and humid here i play golf in the uk and can hit drives up to 270 yards and hit five iron about 190 in april now i;m hiting it about 170 over here plus there is no wind or anything like that.