The maximum ambient temperature will depend on the desired reliability, the heat sink, how much heat is being dissipated, and the temperature rating for the module or other system components (such as fans and insulating materials). Typically the maximum ambient temperature is limited to approximately 50 °C for standard coolers that use fan-cooled heat sinks. Coolers that use high-temperature modules are able to operate at higher ambient temperatures though. However, most commercially available fans have a maximum operating temperature of -20 °C to +100 °C. Be sure to consult with us to verify whether operating in higher ambient temperatures is possible.