I live in a "year round warm climate" so no personal experience, but I have heard of moisture freezing in the shifters before - there should be a rubber boot (the #1 shift boot) that sits between the shift lever and the neck of the shift tower to keep the moisture out, but these have a way of coming apart with age & time. The boot is not available separately, but is only sold with the lever assembly - it can however be replaced with a section cut from a steering rack boot - if you need to do this, installing the replacement on the shift lever can be challenging because it sits in a narrow part of the lever (you'll see what I'm talking about when you take it apart) - lube it with dish washing liquid and gently slide into place.