Aging an imperial stout

I’m going to brew an extract imperial stout. Based on some of the comments I’ve seen, this type of big beer improves with aging. I plan on transferring it to an extra corney keg after fermentation is complete. If I condition it for 9 months or so, how critical is temperature control during that time ?

If I leave it in the garage it will be subject to some temp swings over that time period. I understand the importance of temp control while it’s fermenting but what about while conditioning over a long period ?

You’re much better off if you can avoid large temp swings. There was an experiment done in BYO a while back, focusing on storage conditions. IIRC, there were some differences between cold storage, cellar temps, and room temp. But the main finding was that fluctuating temps were the most detrimental to beer quality.

Why not just store that corny in your basement? Tuck it away in your utility room or something.