subzero C is trivial - I can't think of any electronic device that CAN'T operate well below 0 C

 subzero F is trivial as well unless some sort of "optical read device" is involved, where condensation can cause issues for the read device.

 Military electronics is COMMONLY specified to at least -40C and usually -55 C - but the PARTS themselves don't tend to be any different inside other than the "recordkeeping makes it easy to trace the lot if you have a bad part" type stuff.