My workshop is a small garage, on the side of the house. I live in central EUrope, so it can get high 20’s/ low 30’s in the summer, and drop to -10 in the winter. The wood movement with changes in temp and humidity can affect you (I had a box lid that was perfectly flat in the workshop, but bring it inside and you could serve tea in it, it had cupped so much. Took it back out, cup disappeared). You may want to think about a small toolbox for some of your tools, so that you can close it and put silica gel packets inside in case you don’t go to the workshop for a while. You may also want to build a small tote for your finish and glue (there are storage conditions for these things, as well as use conditions), so that they are easy to bring inside should the temperature fall below 5 degrees. I have a small electric oil heater for the winter here, to keep the workshop at a balmy 8 degrees.
Colin, Czech Rep.