Hannukah is celebrated in the Hebrew month of December. According to the Hebrew calendar, this is first started on the 25th day of Kislev. The Kislev can happen from late November to early December. This tradition actually started even before Jesus was born. This tradition is being done to celebrate the time when the Jews stood up to their oppressors even when they were outnumbered.
All of the days of Hanukkah are considered to be important. There are usually blessings that are being done. There are also some festive foods. Hanukkah is meant to remember all of the triumphs and sacrifices that were done by the early Jews.