Songfacts®:

• This piano-based piece has become a Christmas favorite thanks to its use on the 1965 TV special A Charlie Brown Christmas, where the Peanuts characters sing the song. The vocal version runs 2:47, while an instrumental version goes 6:07.
  
  Vince Guaraldi, who composed the tune, also wrote the score for the special, which is the famous Peanuts theme music (the song is actually called "Linus and Lucy"). Using jazz in a children's special was very unusual, but it was a brilliant choice, helping the special appeal to both kids and adults.
• Originally, this was an instrumental piece that Vince Guaraldi wrote to open A Charlie Brown Christmas. About a month before it aired, Lee Mendelson, who produced the special, decided it might work better with some words, so he wrote the lyric in about 10 minutes sitting at his kitchen table. "It was a poem that just came to me," he told PRI in 2014. "Never changed the words to this day. It was only about a minute long."
• A Charlie Brown Christmas used real children (mostly culled from producer Lee Mendelson's neighborhood) to voice the characters in the special, so the voices on this song are also kids. They are not the same group of children though - "Christmas Time Is Here" is sung by a group of kids Vince Guaraldi put together.
• This was used in the movie The Royal Tenenbaums and as the "sad" theme on the TV show Arrested Development. >>

  Suggestion credit:
  Bertrand - Paris, France, for above 2
• Dwight Schrute is not a fan of this tune. In The Office episode "Christmas Wishes" (2011) he angrily calls it garbage and starts playing Trans-Siberian Orchestra's "Christmas Eve/Sarajevo 12/24" instead.