UV protection is reason enough to cover them. Sunshine doesn't care what the temperature is and can damage your tires any time of year. Any time the vehicle sits for more than a month without moving it a good time to put on the covers. The absolute BEST way to protect the tires is to keep them rolling though.
Good luck / Skip
2011 F-150 HD Ecoboost 3.5 V6. 2550 payload, 17,100 GCVWR -
2004 F-150 HD (Traded after 80,000 towing miles)
2007 Rockwood 8314SS 34' travel trailer
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