No classes on full or new moons.  
Times given are specific to Santa Cruz:

2021
December 3 - Friday - New Moon, 11:43 PM
December 18 - Saturday - Full Moon, 8:35 PM

2022
January 2 - Sunday - Super New Moon, 10:33 AM 
January 17 - Monday - Full Moon, 3:48 PM
January 31 - Monday - Black Moon (2nd New Moon in one month), 9:46 PM
February 16 - Wednesday - Full Moon, 8:56 AM
March 2 - Wednesday - New Moon, 9:34 AM
March 18 - Friday - Full Moon, 12:17 AM
March 31 - Thursday - Black Moon (2nd New Moon in one month), 11:24 PM
April 16 - Saturday - Full Moon, 11:55 AM
April 30 - Saturday - New Moon, 1:28 PM
May 15 - Sunday - Total Lunar Eclipse, Full Moon, 9:14 PM
May 30 - Monday - New Moon, 4:30 AM
June 14 - Tuesday - Super Full Moon, 4:51 AM
June 28 - Tuesday - Micro New Moon, 7:52 PM
July 13 - Wednesday - Super Full Moon, 11:37 AM
July 28 - Thursday - New Moon, 10:54 AM
August 11 - Thursday - Full Moon, 6:35 PM 
August 27 - Saturday - New Moon, 1:17 AM
September 10 - Saturday - Full Moon, 2:59 AM
September 25 - Sunday - New Moon, 2:54 PM
October 9 - Sunday - Full Moon, 1:54 PM
October 25 - Tuesday - New Moon, 3:48 AM
November 8 - Tuesday - Total Lunar Eclipse, Full Moon, 3:02 AM
November 23 - Wednesday - New Moon, 2:57 PM
December 7 - Wednesday - Full Moon, 8:08 PM
December 23 - Friday - Super New Moon, 2:16 AM