Epoxy likes to be used in 70-80 degree temps for a nice flowing viscosity and average curing time. Cold temps will thicken the epoxy making it difficult to laminate and take longer to cure. It can be used in temps in the 40's with no issues - the resin just needs to be warmed up to reduce the viscosity and allow it to flow. You want to heat the RESIN component only (never the hardener) in the microwave for 2 seconds per ounce or set the bottle near a heater until it flows like water again.If you can heat up the blank as well it helps keep the resin warm while working with it.... not 100% necessary but helps.