On Mon, 19 Nov 2012 15:26:14 -0800, Kate wrote:

Is it safe to leave the battery, unplugged, in the mower which is stored
in the shed, or is it best to store the battery inside where it is warmer?

Best is to bring it inside the garage or basement where it won't freeze
but it will stay cool (refrigerator temps are great for batteries) - and -
to charge it periodically with a trickle charger while it's being stored.

But it will last outside just like all driveway gates do.