H335 is cannister grade WC844, a St. Marks manufactured military ball ammunition powder developed for the 5.56 NATO round and used in M193 and M855 and their corresponding tracer rounds. As you might imagine, military powders have to work over a wide range of temperature conditions so you can expect the powder itself will continue to function suitable rifles over such a range. On the other hand, military ball ammunition accuracy requirements are not normally high by civilian marksmanship standards. You also may have noticed the military uses stick powders in their match and sniper ammunition. That said, a number of folks have reported more modern spherical propellant formulations, such as the Ramshot line and the newer Alliant and Hodgdon powders don't necessarily have either the fouling or the ignition difficulties that the older military formulations did so this is a fluid situation and, as always, you'll have to test these in your own guns to find out what they will or won't do.
Denton Bramwell shows pretty convincingly
that barrel temperature matters to performance much more than powder temperature. Thus, cold barrel vs. warm barrel should be your primary concern. Cold weather function for civilians is mostly about hunting where a cold barrel shot will be made. Unfortunately, icing a barrel up in warm weather means condensation, so this is not a test normally looked forward to.