# Field Archery, high humidity causing low arrows?



## ThunderEagle (May 11, 2011)

Well, all I can do is relate a story from last years Ohio's State Field shoot. In the morning, my group had the yardages match with our Range finders, and we shot them dead on. In the afternoon we found that we were a yard or so short on everything we shot, despite our range finders still getting us the yardage dead on. We added at least a yard to everything.

No idea if others found anything similar.


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## eclark53520 (Sep 11, 2012)

Drastic changes in Humidity will affect the flight of the arrow, however, in completely the opposite way. 

Water vapor has a lower molecular weight than that of air, therefore more water vapor in the air means air is less dense than that of regular 'dry' air. Meaning air with a lot of moisture in it should allow the arrow to fly faster than that of 'dry' air. This has been scientifically proven.


It does seem to have an effect on archery though in the manner in which you describe. Lots of archers have shown a lack in velocity when the air is heavily humid. I have a feeling the humidity is causing a change in the bow string, causing the arrow to be launched with less velocity to begin with, not the arrow slowing down because of air conditions. I have no proof to back up this particular claim though.


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## SonnyThomas (Sep 10, 2006)

No, I haven't found humidity a factor. Worst humidity ever in 2005. We were soaking wet from sweat just walking to our first target. Our shirts were hanging almost to our knees by target 7, that soaking wet with sweat. There wasn't a dry stitch on us and my billfold was wet clear through. Yeah, had to hang out everything in my billfold when I got home. 
Shot ASA 3D State Championship in 2011 in pouring down rain from target 1 through target 30. The only ones that I saw have issues with the rain were the Traditional shooters. Bow strings not having the pressure like compounds, their bow strings would load up with rain. To get on target they'd have to twang their bow strings to get rid of the water and then they'd be dead on....


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## bigHUN (Feb 5, 2006)

I believe yes the humidity will effect the string speed, not as much as shooting in a rain or with a freshly waxed string but stil noticeabl. Also as the light goes around during a day will effect the distances and the L-R for couple clicks...you just sighted in yesterday at full bright light and today is way less light and more gray no contrasts, the POI can and most likely will be off.


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## grantmac (May 31, 2007)

In general humidity has less effect on ballistics then temperature or altitude.

It doesn't have a fairly profound effect on the drag of cables through pulley systems in my (purely anecdotal) experience.

-Grant


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## yeroc (Jan 11, 2007)

no ive never had an issue with humidity.i believe it can affect string speed but as long as your string is waxed up shouldnt be an issue.if your referring to the state 900 rnd in pekin i was there also.was very humid


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## EPLC (May 21, 2002)

Well, I shot the NE Outdoor Sectionals this weekend and Saturday was nice and Sunday it rained hard off and on throughout the shoot. I noticed absolutely no variation in my yardage marks throughout the shoot. They were spot on last week and again today. I was actually surprised that I had to make no adjustment due to the rain yesterday. It just may be a case of how stable the string set is on various bows.


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## SonnyThomas (Sep 10, 2006)

yeroc said:


> no ive never had an issue with humidity.i believe it can affect string speed but as long as your string is waxed up shouldnt be an issue.if your referring to the state 900 rnd in pekin i was there also.was very humid


Yeroc finished 3rd behind two of the finer Illinois outdoor 900 shooters. This was a State Championship.


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## montigre (Oct 13, 2008)

I think the relative heat index has some to do with a string getting slower. On a sunny humid day, I usually have to add a little yardage as the day progresses as opposed to a rainy cool day where my marks remain the same throughout the shoot. I don't really understand the science behind it, just something I have noticed shooting in the balmy summer months.


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## EPLC (May 21, 2002)

SonnyThomas said:


> Yeroc finished 3rd behind two of the finer Illinois outdoor 900 shooters. This was a State Championship.


I had a good weekend myself


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## yeroc (Jan 11, 2007)

good job eplc.im proud of how i shot.illinois is tough state.shooting against guys with reigning national title i was pleased just to place and be within 3pts of them.


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## RickT (Mar 14, 2009)

EPLC said:


> I had a good weekend myself


 Congratulations Paul!!


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## SonnyThomas (Sep 10, 2006)

Congrats, EPLC!


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## EPLC (May 21, 2002)

yeroc said:


> good job eplc.im proud of how i shot.illinois is tough state.shooting against guys with reigning national title i was pleased just to place and be within 3pts of them.


I assure you the competition wasn't quite as stiff here but I certainly was pleased with the outcome. My best at this shoot in prior years was 3rd (last year).


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## jim p (Oct 29, 2003)

Find a formula to calculate density altitude. The higher the temperature and humidity and actual altitude. The thinner the air is and the faster an arrow will fly and the faster a string will move. High humidity should give higher hits.


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## snowshovler (Oct 15, 2011)

The issue might not have been the humidity effecting air density but the location of the sun from morning until the afternoon might be the culprit. When I was target shooting rimfire rifles with peep sights the angle of the sun reflecting off the targets was different and presented a different "look" then from the morning. As the day progressed and the sun went up it was necessary to add clicks to shoot higher. Lights up, sights up was the adage. The humid air might also have refracted the light a bit (moisture will have bent the light down) causing the change in POI/POA.


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## bigHUN (Feb 5, 2006)

FITA tournaments are all day events, or almost, starting from about 9 in the morning and most likely will last at least up to 4+ afternoon.
The worst ranges where we shoot towards South (or North) because the sun comes up from left and moving to the front and ends at the right side. That day lot of L-R misses.
I like that range what I am shooting towards East, the sun is always moving to the right around me, but is hard to see through a peep late afternoon when the sun comes to the corner of my eye.
The Field again have lot of turns and twists, along the day just keep clicking the sight.
Worst thing again if you sight in at a sunny day (as I just did last week) and next day is gray and no contrasts, I just had that case over weekend, my distances were off buy 1.5 yard short, then the rain started and slow down the string for about next 5-6 fs ....
Last year- mid summer time I learned also that don't wax the strings in the airconditioned basement night before the tournament and next day was a record heat, the string was splashing the wax out a whole day resulting a disaster score...
Many things on the table to talk about.
I just finished lubing my bow in the basement, it was all in rust from last rain I could feel each cam were moving different....soaked the cables/string as well with scorpion lube let see tomorrow if I can group tighter...


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## Slabbro (Nov 4, 2012)

EPLC said:


> I assure you the competition wasn't quite as stiff here but I certainly was pleased with the outcome. My best at this shoot in prior years was 3rd (last year).


What class do you shoot? I was there in AMFS. Only the second time I have shot it and shooting a bow that was new, few weeks old, and took 7th. Thinking I know you maybe. I'm Don from Havana Outdoors.


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## EPLC (May 21, 2002)

Slabbro said:


> What class do you shoot? I was there in AMFS. Only the second time I have shot it and shooting a bow that was new, few weeks old, and took 7th. Thinking I know you maybe. I'm Don from Havana Outdoors.


Male SS FS but I think we were at different shoots. This was the NFAA NE Outdoor Sectional. https://www.nfaausa.com/sites/default/files/NE Outdoor Sectional results Sheet1.pdf


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