Anything wrong with leaving brass powder and components in a garage? It's improved but still subject to a bunch of temp fluxuation and humidity I would think.

I used to reload in the garage. Then one spring we had a really humid thaw...one of those days when it goes from 20s to 50s overnight. There was tons of fog and moisture everywhere. My press went from looking like new to being covered in surface rust in one day. Everything is now in the basement, along with a dehumidifier.

I wouldn’t like the temperature swings. I’ve had it where metal tools in the garage were coated with condensation. That of course isn’t good over time.

Some type of setup where you store inside, but reload in the garage could be workable. That would require moving stuff more often than desired.

Here in the Midwest a basement is almost mandatory. I realize in some areas they can be less common for various reasons.

Cool, I may consider running a vent out there to regulate the temp a bit. Might just be best to keep it inside though. Thanks for the info.

Done it for years, but I’m in the high desert, so humidity isn’t much of an issue. Also, the garage is insulated. I wouldn’t be so unopposed in a more humid region.

My reloading bench is in the unheated/uninsulated garage, but I keep all my powder in the house and only take it out to the garage when I'm loading. Brass and bullets live in the garage. Primers are kind of split between the two but with summer approaching the garage will be pretty warm and sometimes humid, so I think I'm going to move all the primers inside too. I'll have to put in a shelf someplace - I've got a lot of primers. It gets a little muggy here sometimes in the summer and fall, but not like some other places.

 
Reloading bench, press, and tools, etc. are in the garage. Powder and primers are kept inside the climate-controlled house closets, in separate locations about 50ft apart.

I keep everything in the garage. During the winter, I use a heater to keep things above freezing. During the summer, the 12" slab of concrete it's built on keeps everything cool, about 70 deg.

I've never seen a difference in any of my loads. They all fire reliably and have constant velocities when measured!

Quite frankly, I would worry about the 40 deg to 50 deg temp swings on the powder or primers!

I keep most all of my primers and powders indoors but not all.
Everything else is in the garage.
Mostly because there is not enough room in my jam-packed garage but partly due to security and climate control.
My garage is insulated but only heated or ac's when I am out there.
It doesn't swing too terribly but it does some.
YMMV

I think it depends on where you live. I live in Florida and the temp in the garage has reached over 100 degrees in summer with very high humidity.

I store my brass and reloading equipment in the garage and I see no ill effect with brass. I save all my reloading for the winter months garage temp @ around 70 degrees.

All powder and primers stored in air conditioned man cave at around 75 degrees year round 45% humidity. I just finished a can of RedDot I’ve had since the 70s and it has been as good as it always was stored that way.

I have lots of reloading equipment and the only thing I have had to rust was a RCBS stuck case remover kit. Every part in it rusted and it was in the original box stacked with die sets that did not rust.

I'm in Central VA, a very humid place,

my Garage is insulated, but no AC,

seems to never get above 90, never below 40, (we have an insulated bedroom over the garage)

no issues what so ever