DanD has the most likely solution to this issue. Also sometimes the grease to lubricate the starter drive shaft will impede the motion to engage the flywheel.
Fisherman, there is truth to the marine guys statement. Although I leave my battery inside my boat (disconnected) I do charge it once through the winter, just in case.
A charged or even semi charged battery will not freeze. Battery's will deteriorate faster in warmer temperatures, it's when the cold arrives that the bad ones show up when more amps are required to crank. The cold will actually make your stored charged battery last longer because less chemical reaction is taking place.