Basic round outdoor clock with thermometer

Recently, the clock hands got caught up with the thermometer needle which has caused the hour hand to not register the time correctly.  For example, the minute hand will register on the hour (i.e. on the 12) and the hour hand will register about 15 minutes before the hour.  Given that there is a plastic cover on the clock, I cannot simply adjust the hands manually.  I am not sure what to do other than return clock which was bought less than one year ago; however, I do not have the UPC to register and make a claim.