High Humidity

[thom]

Looking for info on reloading and humidity. I have my reloader setup in the shed out back. I have a fan to move around the air, that's it. Is there a humidity limit in reloading that would affect the powder that anyone knows of? I try to do it when the outside temps is lower than 80 degrees.

Thanks,
Thom

 

[SupportTheSecond]

From many articles I've seen low humidity is a concern vs.high.

 

[samnev]

I've noticed that shortly after the monsoon started and the humidity rose to present levels my RCBS ChargeMaster has slightly more powder drops with W748 which is a very fine powder. Before that <1% would be off and only by 1/10 of a grain or so. Strangely IMR 4895 drops hasn't been affected. just a coincidence, who knows?

 

[Suck My Glock]

It years past, I have occasionally experienced powder getting "clumpy" if it was exposed to the air and not sealed up in containers or the measure. But after the humidity abated and returned to normal dryness, the powder would return to its regular fine and non-clumpy state. I never did load any while the powder was in such a state, because it was so miserable in the garage while that humid, so I stayed inside.

I've always been aware that extreme temperatures can affect velocities, but never been told whether humidity at time of loading had an effect.