It seems the most previous info and advice is about the temperature transition as it moves from one environment to another, and the cautionary advice is to allow the guitar to warm up (or cool down also, I assume) by keeping it in its case during the warm up or cool down period. Rapid temperature changes may cause checking of the finish.
Since it won’t be freezing when you’ll be playing, it’s unlikely that you will be in this situation. I never heard of any restriction about actually playing in cold weather. How many people gig outside in below freezing weather? Not many, probably. I’m sure that you’d have to check and adjust your tuning frequently until any temperature changes stabilizes, at any degree temperature difference. I don’t think you will have any problem with your bass guitar playing it above freezing. Look for and promptly wipe dry any moisture condensation as it transitions from cold to warm. That’s all I have. Here’s a couple of discussion links you can read:
viewtopic.php?f=1&t=4185&p=46960&hilit=Cold+weather#p46960viewtopic.php?f=1&t=7985&p=96298&hilit=Cold+weather#p96298Anyone else have some advice?