This is an entry in our Disneyland 101 Glossary: Disneyland Resort definitions in under 101 words, from Mouse Brief.
Holiday Time at Disneyland Resort refers to the season from mid-November through the New Year when Disney collectively celebrates Christmas, Navidad, Hanukkah, Diwali, Kwanzaa and Three Kings Day with seasonal decor, food, entertainment, costumes, music and even changes to some attractions like “it’s a small world” Holiday and Luigi’s Joy to the Whirl. Disney California Adventure Park hosts Disney Festival of the Holidays, and Disneyland Park features A Christmas Fantasy Parade. Each park enhances their nighttime spectaculars with festive touches and “snow” falls at scheduled times around the resort. All of these offerings are included in general admission.