Cold is usually not a big deal, but anything above 80 or so for extended periods would be a bad idea. Also, and maybe more important, would be the possibility of higher humidity in a garage. That would be a huge problem.
Humidity most likely should not be a problem.
All supplements are in jars with screw tops.
I would open the jars indors where I keep about 75F.
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Note on temperature;
for long time my comfortable indoor summer/winter temperature was 77F.
Whenewer I can I am in shorts and no shirt.
Lately I prefer 75F when sitting iddle.
I think it may have to do with my (hopefully) better adjusted thyroid.