The answer to this entirely depends on the type of Dash Cam you have been using or looking for. Such cameras are either made of lithium-ion batteries or have supercapacitors.
With batteries, it may not be able to withstand heat at all while the capacitor-powered dash cam has the ability to withstand extremes of temperature. Apart from this, if you wish to save your dash cam from heat, simply mount the cameras in a location that has minimum sunlight in your car.