TIME Magazine has the following article on their website:
It began last night at sunset: Hanukkah. Or is it Chanukah? Or Hannukah? Sometimes getting the proper spelling of a Hebrew word transliterated into English gets tricky, especially when far more than a trio of options prove technically correct. But if you don’t fall into the Hebrew-scholar category, what should you do?
With so many ways to correctly get the point of Hanukkah across, the proper spelling really turns into a matter of preference and mass appeal. If you want to fit in with the crowd, opt for the Hanukkah spelling, now the most widely used of the choices.
However, don’t forget Chanukah, the second most often used spelling and the favorite of traditionalists. Just how did Hanukkah‘s spelling become so popular and oust Chanukah atop the list? You can blame it on the ch sound being similar to the H sound, making Hanukkah a bit easier for English speakers to understand the pronunciation.
As little as about five years ago, the top spelling choice on the Internet was Chanukah. But times are changing, even in the way the Jewish holiday of lights is celebrated and understood, and the Hanukkah spelling has gone mainstream. So, if you like to slightly buck the trend and go old school, Chanukah is your spelling.
With both correct, and about 14 others technically correct too, rest assured that you’ve got a pretty good shot at getting the spelling right. Whether you’re in tune with the latest spelling trend will be an entirely different story.