I need to seal up some rice, lentils and split peas in mylar soon but I started wondering with all the rain is now a bad time because there is more moisture in the air or does it not make that much of a difference? If it can be a problem how should I determine when is a good time, higher heat and no rain for 3 - 4 days? If I placed the dry goods in a room with a dehumidifier for about 24 hours and then sealed them up would that help? I know baking at low temps can take extra moisture out but that's a bit hard to do with 200 lbs of product.
This is just a guess on my part, but unless you have moisture condensing out of the air on the walls/windows/etc. I wouldn't worry about it too much. I've put rice, beans & wheat berries into mylar bags & buckets in the middle of TN summers (i.e. VERY humid, to the point I need to have fish gills implanted to breath LOL ) and never had a problem. If you are inside and your home A/C is running then you are already dehumidifying the air in your home. My typical proceedure is to freeze the product in a chest freezer for 48 hrs, allow to warm to room temp for 24hrs (this allows condensation to leave) then into mylar bags with O2 absorbers and sealed inside a 5 gal bucket. Overkill? maybe, but an once of prevention is worth a pound of cure. Good luck