I'd say no major worries. I've had a passive basement cellar for about 6 years. Mid-to upper 50s winter, upper 60s summer. Humidity OK (never below 40-50%). Downside, it's in the corner of my laundry room, so it's not completely odor free and gets vibrations and a 2-3 degree temp increase for a couple hours 1-2 days per week (though not for long enough to likely have much impact on the actual wine temp). To a purist, that's gotta sound like a bad setup (I hear you cringing ), but it's the best I can do right now in my house.
Results to date: over the last few months I've opened 5-6 bottles that have been there since close to the beginning. Only one seemed at all "advanced" and none had any off characteristics that my meager palate could pick up. The one that was a bit advanced was a 2002 Napa Merlot that had slight bricking, but was delicious and probably wouldn't have been more than a 7-8 year wine regardless of storage. Would I risk storing first growths for 30 years in those conditions? No, but my experience gives me no concern that I can't get good results for 10 years or more.
I'd love to hear others' experiences with "non-ideal" cellaring with similar temp ranges.