At the end on this page there is a graph displaying the pressure for variuos propane and butane blends, both in metric and imperial.
http://www.engineeringtoolbox.com/propane-butane-mix-d_1043.html
The "normal"(short and fat) one time cannisters is rated to 20.5 bar of pressure, the heavier cannisters, such as Sievert 2206/2207, rated for pure propane is often rated to 26-27 bar, not that much difference. In temperature it means that the onetime cannisters is good to 61 degrees celsius and the heavier "propane cannisters" is good for 74 degrees.
I'm not sure about the Coleman and the other cannisters talked about in this thread, we don't have tjhem here in sweden so I dont know about them.
So for winter use it's definately possible and not "that" unsafe. But leaving a refilled cannister in a hot car… KAAAABBBOOOMMMM!
It's definately possible but I would sure as hell never do it! Whitegas or remote cannister stove for me.
