While there were a few early stragglers to Christmas Music this year (starting with 1220/98.1 KOMC Branson MO on October 1), all of them were stations preparing to debut new formats or brand new signals signing on for the first time.
Today we had the first stations to make their annual move to the format: SummitMedia Soft AC “Easy 102.1” 1320 WENN/W271BN Birmingham AL, iHeartMedia AC “105.3 My-FM” 1270 WTLY/105.3 W287CO Tallahassee FL, and iHeartMedia Classic Country “96.1 The Legend” W241AF/WUSY-HD2 Chattanooga TN. While there’s usually a group of stations to flip to Christmas music in October, most of the seasonal flips will take place once the calendar switches to November next week.
INSTANT INSIGHT: In past years we’ve created a list of stations on the RadioInsight Community that have flipped to All-Christmas, but now that we’re fifteen years in to this going from a fad to a tradition it is very predictable when most stations will flip to Christmas music for the holiday season. We will still track those stations that blow up their existing branding and using the holiday music as a lead-in to something new for 2017.
Tom 
JayR 
Joseph_Gallant 
94.9 KCMO-FM has announced that they will flip to Christmas music again this year, but have made it into a contest. Whoever comes closest to guessing when they flip will win a trip to Cancun.
http://www.949kcmo.com/2016/10/16/901023/
Where does WMJX-HD2 fit in? With the exception of a few weeks when they swap formats with the main signal they play the Christmas music format year-round.
I would expect that very soon, Boston ‘s WMJX-106.7 (“Magic 106.7”) will swap formats of their analog/HD-1 signal and their HD-2 subchannel, putting all-Christmas on analog/HD-1, and their regular format on HD-2.
Although the “Inside Track” page of the Boston Herald reported this past Thursday (October 28th) that both it and Hot AC WBMX-104.1 (“Mix 104.1”, which has never gone all-Christmas) might go all-Christmas as early as this Tuesday (November 1st), I doubt that WBMX will do so nor that WMJX will do so as early as this Tuesday.
I suspect WMJX will go all-Christmas no sooner than mid-November……unless someone else in Boston does go all-Christmas first, in which case, “Magic” will jump-in quickly, perhaps within a few minutes of a competitor doing so, whether that competitor is “Mix” or someone else.
HD subchannels without analog translators have so few listeners that they really don’t count.
On their Twitter feed, WEZW-93.1 in southeastern New Jersey has posted that they’ll go all-Christmas this Tuesday (November 1st).
For WEZW, that would be late: The last few years, they switched to all-Christmas some two weeks before Halloween.
With the flips reported above, I think you may see a lot more stations flipping on November 1st than in the past.
I see three reasons:
(1) To “get the jump” on possible competitors in their market. But if more than one station in a city goes all-Christmas, any other station thinking of doing so would follow suit within minutes.
(2) The nasty election campaign. By going all-Christmas a week before the Election Day (which this year is November 8th), stations can even promote themselves as being a place for listeners to get relief from those nasty political ads (remember that few political spots air on music-formatted stations; most political ads on radio go to all-news, news/talk, or all-talk stations).
(3) And the other reason is the retail industry, which provides most of the advertising revenue for most music-formatted stations. Many “brick and mortar” retail chains have been struggling of late (as opposed to online retailers like Amazon). Some major “brick and mortar” retailers, if they have a horrible Christmas-shopping season, might not survive long enough to see the 2017 Christmas season.
I could actually see retailer advertisers and their agencies pressuring radio to play more Christmas music and to start it earlier.
That’s why I suspect you may see dozens of stations going all-Christmas this Tuesday (November 1st), a lot more than on November 1st in any previous year.
Note that two of the three newest all-Christmas formats are owned by iHeart Christmas (a/k/a iHeart media), which is the most aggressive broadcaster as regards all-Christmas formats.