Eventhough we do not have any record of the actual date of birth of Jesus Christ, Christians have, for centuries, been celebrating Christ's birthday on December 25. The actual date is immaterial; what is important is the significance of the celebration.
Christmas is a joyous occasion: a time for family reunions, gathering of friends, parties, gift-giving, carollings, decorating houses with bright lights and red, green and gold trimmings. For Christians, Christmas has a deeper meaning. It is giving thanks to God for sending His Son to save us from eternal damnation because of our sins. "For God so loved the world that He gave His only begotten Son, that whosoever believeth in Him should not perish but have eternal life." (John 3:16, KJV). Jesus Christ is the reason for the season.