The temperature range is determined by the base elastomer used.  This chart depicts the maximum  temperature range for each elastomer.  The temperature range for a specific compound may not reach these maximum limits.  Higher temperatures may be considered if exposure is short or intermittent.

Material Low end Operating Temperature High end
Operating
Temperature
Aflas® 25°F 450°F
Butyl -60°F 250°F
EPDM -40°F 250°F
FFKM (Perfluoroelastomer) -10°F 500°F
Fluorosilicone -60°F 350°F
HNBR -20°F 300°F
Neoprene® -30°F 225°F
Nitrile -30°F 250°F
Polyacrylate -10°F 300°F
Polyurethane -40°F 175°F
SBR -20°F 212°F
Silicone -60°F 400°F
Viton® or FKM -10°F 400°F