Casting is something to not take lightly. Humidity is dangerous, but actual
moisture can cause serious injury. If moisture works into the melting pot where the hot molten lead is cooking, it can cause the moisture to rapidly evaporate and will explode molten metal out of the pot onto anyone or thing. Sweat, rain, all of that has no place around molten lead when casting. I am very moisture careful when I cast.
I have heard it suggested that when humid out, ventilation is even more critical when casting as the lead fumes can hang in the moisture laden air and make it easier for the caster to breath in the fumes. Whether there is basis in that, I do not know. I have casted in humid conditions, but I take frequent breathing fresh airbrakes.
If it is very cold, also watch for humidity forming on the metal that has not gone into the melting pot. Ice cold metal can hold moisture and if you drop that into molten lead, it can cause the molten lead to explode. I often times warm any lead about to be introduced to the melting pot over a flame for a few seconds just to warm it and to remove any moisture that might have formed. I find there is less reaction then when I introduce the fresh lead to the molten lead.
We had some nasty weather here last evening. It actually rained here in Northern Wisconsin. Hard to believe raining in January. Anyway it turned our roads into ice skating rinks. They warned all motorists to not leave their homes unless an emergency. Today it is snowing. So instead of range time, I have been working on some rifles.
I threw a Nikon Pro Staff 2-7x32mm on a Knight Disc rifle. Using Warne QD rings I think it makes a nice looking outfit. I will shoot that tomorrow.