I have 6 of them sitting on the concrete floor of my non-climate controlled shed, Mow. When I slap the charger on them about once per quarter, it takes a whopping 5 minutes before they report fully charged.
You should never let your battery be dead. Prior to seasonal storing, the battery should be fully charged, and electrolite topped off (on non-sealed batteries). Extreme cold should be avoided. A starting battery should never be discharged more than 25%. Even a deep cycle battery should never be discharged more than 50%. Assuming you want any kind of life out of it.
A single complete discharge of any battery shortens its life and reduces its capacity significantly.
Getting back to the original post, I hope you didn't pay for that new battery.