Cold: Some of the dice (and other products) have liquid cores. I take regular precautions to prevent freezing, but as with most liquids they can freeze if exposed to extreme cold temperatures. This can cause the cores to crack or break. If you are shipping to a location that is currently experiencing freezing temperatures, I urge you to choose "Cold Protection" to help mitigate any damage. "Cold Protection" lets me know to pack your order with increased insulation and I will upgrade the shipping method to USPS Priority.  Hot: All of the dice (and other products) are made with premium epoxy resin. While they are safe and sturdy to use in warmer climates, resin can become soft or pliable if left in extreme heat for extended periods of time, causing your product to warp.