Kindling Hanukkah (Chanukah) lights is the most important Hanukkah custom. Jews light Hanukkah candles to remember the miracle of the Maccabees victory and the miracle of the oil that burnt for eight days in the holy Temple. It is a mitzvah (commandment from God) that Jews "publicize the miracle" by lighting a Hanukkah Menorah each night during the eight days of Hanukkah.
The Menorah should preferably be lit immediately at nightfall. If necessary, however, the Menorah can be lit late into the night. It is best to wait until all members of the household are present to light the Menorah. The Menorah should remain lit for at least 30 minutes after nightfall. On Friday afternoon, the Menorah should be lit before sundown.