I have both carbon and aluminum arrows that are matched to my long bow and both fly equally straight and true, but since we have been plunged into a deep freeze - temps in the teens and twentys - my aluminum arrows are doing some funky moves during flight and hitting the target at slight angles. The carbons are still true. Will the cold change the spine of the aluminum arrows?

There was a testing done that I know of a few years ago on the 13 wall aluminums.  A lot of shooters where haveing trouble with them in the cold.  They were actually put in a freezer and found that they would not shoot groups at 20 yards but in normal heat they would.  Now this was only on a thin wall mind you.

Metals expand and shrink a lot more in hot and cold temperatures than carbon fibers glued up in a matrix do.

Cold could also change the bow dynamics.  Not to mention shooter dynamics.  I try to spend more time shooting than thinking about things I cannot control.  H

I was told that in the winter a aluminum shaft can pick up 5-10# of spine. It has been real cold here to and I have noticed a difference in my alum arrows until I shoot them a few times. The guy that told me about the shafts was a rep for Easton at that time, met him At Harrisburg show in 1988.  

The folks at ACE told me wood arrows would definitely spine heavier in cold weather.  I have seen about 5# in my testing so far.

Dave

Wood arrows definitely do: Higher spine in cold temps, lower spine in hot, humid weather.

It seems only natural that both wood and aluminum would change spine in weather extremes; and I agree with 'Ground Hunter'.  I'll bet the shooter dynamics have more of an affect on the shot. By the time I bundle up, I have more of a chance of hitting my bow arm with the string, not to mention the angle my elbow makes with the added clothing.

Thanks to all for the info; at least now I know I'm not crazy.    :eek:

I would think that you are most definitely correct in your assumption. My knees, my shoulders, and my fingers tell me that you are properly assuming the results of cold weather. A bit of warmup for the body and the bow, (arrows included) will enhance performance.
Even oil, doesn't flow well when Brrrrrrrrrrrrr
cold.