Quoted from MrBally:It needs to be climate controlled year round.
Keep in mind that there are two kinds of climate controlled units. Units that are actually at a consistent set temperature, and units that have a large swing range from something like 50'F-80'F. Swing temperatures are not good for pins, especially during the weather transitions between seasons.
For any space, take advantage of as much vertical space as possible.
I found that these racks are a good fit for backboxes: https://www.lowes.com/pd/edsal-24-in-D-x-77-in-W-x-72-in-H-3-Tier-Steel-Freestanding-Shelving-Unit/3172913