Apple began closing retail locations earlier this year and many of its stores were shut down for months in the spring. Apple began reopening stores in June. All retail locations in California have a notice letting customers know that the stores are temporarily closed, though some are allowing for order pickups and genius bar appointments through December 22.
Apple has shuttered stores in California as COVID cases in the state have continued to rise, and stores in other places around the world are also closed down right now. According to 9to5Mac, there are nearly 100 Apple Stores that are non-operational at this time.
Stores in Tennessee were closed this weekend, and stores that are located in the UK's Tier 4 restrictions are shutting down as of today. 18 stores in Germany and the Netherlands were closed last week, and stores in Mexico and Brazil are closing this weekend. source