One should preferably light Chanukah candles immediately when the stars appear in the sky, which is approximately fifteen minutes after sunset during this time of year. Some Ashkenazim, however, customarily light at sunset.
The Earliest Possible Time to Light Chanukah Candles
Chanukah candles should not be lit before this time (with the exclusion of Friday afternoon when the candles must be lit before sunset, as will be explained in one of the following Halachot). Even one who is busy and cannot light at the appropriate time may not light before this time, for many of the Rishonim are of the opinion that one does not fulfill one’s obligation before this time, even if one has no other alternative. However, if one is about to set out on a journey and is worried that he will lose out on the Mitzvah of lighting the candles entirely, one may, in fact, light before sunset beginning from the time of Pelag Ha’Mincha (which is one-and-a-quarter seasonal hours before nightfall). Nevertheless, one may not recite the blessings before lighting, as the rule is “when in doubt regarding the blessing, do not bless.” In any case, it is preferable to appoint a messenger to light on one’s behalf and one will thus fulfill his obligation of lighting Chanukah candles in this way.
The Latest Possible Time to Light Chanukah Candles
Preferably, one should not light later than the prescribed time; rather, one should light immediately upon the emergence of stars in the sky. If one did not light at this time, one may still light until the time when most passerby are no longer found in the street (which is about half an hour after the preferred lighting time). Even if one has not yet lit by this time, one may still light afterwards, even if the hour is late, until dawn. However, in such a situation where one arrives home late and finds the members of his household sleeping, it is preferable to awaken at least some of the family members so that they may be present at the time of the lighting in order to publicize the miracle. If one is unable to wake them up though, one may nevertheless light the candles and recite the blessings.
The Time “The Stars Emerge” (Halachic Nightfall)
According to Maran Rabbeinu Ovadia Yosef zt”l, the time in Jerusalem when stars appear in the sky is at approximately 4:52 PM.
In all other places, this time can be calculated by counting thirteen-and-a half halachic (seasonal) minutes after sunset. The formula to calculate thirteen-and-a-half halachic minutes is to divide the day from sunrise to sunset into twelve equal parts. Every part is a halachic (seasonal) hour and each of these hours consists of sixty halachic minutes. This is what causes these thirteen-and-a-half minutes to be approximately ten regular minutes in the winter and in the summer these thirteen-and-a-half minutes can actually be longer based on the length of the day.
In New York City, sunset on the first night of Chanukah is at approximately 4:28 PM and the thirteen-and-a-half halachic minutes are approximately eleven regular minutes during this time of year (Note: Nightfall in the New York throughout the year is approximately 15-20 minutes after sunset according to the Sephardic tradition; for further reference, see Responsa Igrot Moshe, OC, Volume 4, Chapter 62 who rules that nightfall according to the opinion of the Geonim [whose opinion is the basis for the Sephardic tradition] in New York is 9.375 minutes after sunset all year long). Hence, the proper time for lighting Chanukah candles in New York is at approximately 4:45 PM. Please refer to the time of sunset on each evening of Chanukah in order to calculate the appropriate lighting time for the rest of the nights (besides for Motza’ei Shabbat when Chanukah candles are lit later, only once Shabbat has concluded; some even wait for nightfall according to Rabbeinu Tam’s opinion when lighting on Motza’ei Shabbat as we shall, G-d-willing, discuss in a following Halacha).
Praying Arvit vs. Lighting Chanukah Candles
Our custom is to pray Arvit before lighting Chanukah candles in one’s home. If one arrives home and has not yet prayed Arvit, Maran zt”l has ruled that one should go and pray Arvit first and only then light Chanukah candles, for praying Arvit takes precedence based on the rule that “the more frequent of two Mitzvot is performed first”; thus, Arvit is certainly more frequent than the Mitzvah of lighting Chanukah candles which is only performed eight nights of the entire year. If one knows that by going out to look for a Minyan to pray Arvit, one will miss the proper time to light Chanukah candles, one should pray Arvit alone (without a Minyan) calmly and then light the candles. Many people have asked what the source for this ruling is in the works of Maran zt”l and the answer is that this was a verbal ruling offered by Maran zt”l to those who posed this question during his classes and is not written in any of his works.