Those Zebco de-liar scales wont move with a three pound bass on them....Junk!
You are right about the digital scales though, they don't work for beans in the cold.
I would find a good quality spring scale like
THIS ONE. Cold will not effect it enough to worry about.
The weigh a fish with a ruler method also works well. Once you get used to measuring fish, you wont care what they weigh. I like to measure, snap a quick pic, and put them back down the hole CPR style!