Does temperature affect patterns?

[Grant Flaming]

Will the temperature affect how your gun patterns? Will it pattern tighter when it is warmer outside?

[tyelper]

YES AND YES

[bawana]

How much of a difference will you see? Is there any rule of thumb for it?

[chatterbox]

I'm not sure of numbers, but patterns loose alot of density in cold, dry air, and increase that density in warm, moist air.
I'm not sure of the physics and ballistics, but I believe that more dense air "holds" the pattern together better.

[reynolds243]

No different then hitting a golf ball during the summer vs the winter. You will lose 20 yards easy on a drive in cold temps or hitting a baseball in the winter vs summer. Granted its not total apples to apples as the ball has a role in that scenario but you see what i mean.

[chatterbox]

I'm not sure of numbers, but patterns loose alot of density in cold, dry air, and increase that density in warm, moist air.
I'm not sure of the physics and ballistics, but I believe that more dense air "holds" the pattern together better.

Your first statement is true; your second statement is not. The "more dense air" is the colder air, and it spreads the pattern apart. It does not "hold the pattern together better". There has been alot of discussion on this board about the effects of temp. on patterns. Perhaps a search will turn something up.

It would be interesting to see what warm dry air would do to patterns, which would lead to temp being as important as humidity. Say what a hunter that patterns his gun in Nevada, vs. a hunter that patterns in Alabama.
Just more food for thought.

[SumToy]

It will put lower numbers in the cold temps.  Now in cold air you find most is damp and thick.  So you need to go smaller on a choke in the cold temps to keep the gun shooting.  Now the bigger bore guns will be the ones that drop off the most.  The small bore dont have as big of a swing in patterns. 

[reynolds243]

It will put lower numbers in the cold temps.  Now in cold air you find most is damp and thick.  So you need to go smaller on a choke in the cold temps to keep the gun shooting.  Now the bigger bore guns will be the ones that drop off the most.  The small bore dont have as big of a swing in patterns. 

well thats interesting, never thought about the bore diam making a difference.

[Gobble!]

Does a bear crap in the woods?
Temp plays a huge role.
Using Hevi 13 #6s
70 degrees 194 in a 10" circle at 40 yards
30 degrees 140 in a 10" circle at 40 yards

[SumToy]

I will give you a good one.  I have a BPS Trap I punch paper with.   It has a 680 choke and at 60 and up it blow a hole a 58 to 60 ft with a junk 23/4-11/8-9 fed shell.   50 to 60 it is a may be set up.  Below 50 you better off with a box of rocks and a sling shot. 

[ILIKEHEVI-13]

 I have seen a 44 degree day take a Star Dot choke on my 835 that's a hummer in say 60 to 70 degree temp and make it look just mediocre.