In America it is virtually a national holiday, a strangely pagan celebration in such an occasionally puritanical country. By August, its supermarkets are bulging with trick-or-treat paraphernalia, and by September its children are already running around in anticipation of the chocolate-fuelled frenzy they'll be whipped into come October's end.
So why any country would wish to import this commercial juggernaut is beyond me. Which is why, at risk of crossing a line of political correctness, I was somewhat impressed by the investment in Halloween made by the woman in Orpington, a leafy suburb of London, who, when visited by trick-or-treating children, opened the front door dressed in a blood-stained apron wielding a large knife in one hand and a bag containing a lamb's heart. Needless to say, the children and their parents are a tad upset. The woman in question has branded the stunt as a "bit of fun". The Daily Mail is, as I write, still unknotting its underwear over the prank.
While not wishing to condone the emotional disturbance of children, I am quite glad to live in a country (France) that very sensibly eschews the American-style Halloween circus in favour of taking All Saints Day, the day after Halloween, off as a Catholic holiday.
Anyway, for one group of Londoners - let's just call them the players and managerial staff of Chelsea Football Club - Halloween has a habit of marking the start of a particularly unpleasant, particularly traumatic and particularly debilitating tradition known as November.
Because no matter who is in charge, whichever miscreant has been handed the poisoned chalice of being named 'head coach' at Chelsea, the weeks after Halloween have, over the last several seasons, been one long, night sweat-inducing pavor nocturnus.
Last season it happened like clockwork: on October 31, the Blues finished 5-4 victors after a legendary League Cup tie against Manchester United. By November 3 they were drawing 1-1 in a dismal encounter away to Swansea. And then it pretty much collapsed until December: 1-1 against Liverpool on November 11, a 2-1 defeat to West Bromwich Albion on the 17th, a 3-0 defeat to Juventus in the Champions League on November 20, 0-0 against Manchester City at Stamford Bridge on the 25th, 0-0 again against Fulham at the Bridge three days later, and a 3-1 defeat to West Ham on December 1.
Thankfully, December brought a 6 - 1 win over FC Nordsjælland in the Champions League, 3-1 win over Sunderland in the league, 5-1 win over Leeds in the League Cup, and 8-0 over Aston Villa in the league, with wins following away to Norwich and Everton over the Christmas program.
In previous seasons the November to Christmas period - and beyond - has been a source of nothing but frustration followed by recovery at the tail end of winter (accompanied by the inevitable change of manager).
Now I know what you're thinking: one defeat does not a lengthy disaster make. But Chelsea have form here. And with a challenging fixture list between now and Christmas, and indeed over Christmas, Mourinho needs to get to grips with any Groundhog Day-style repetition.
Only Tuesday night sports journalists were wondering whether the Portuguese may have found his formula - including getting better performances out of Fernando Torres and finally realising that Juan Mata is a player of rare creative gift. Four days later and the Chelsea coach is nursing what could be politely called a bloody nose delivered by a Newcastle United who took their chances well.
Mourinho is aware that Chelsea's away form this season has not been good. More importantly, he's also aware of where they are in the calendar: "Of course I am worried, and I read in previous years it happened the same," he told the BBC, noting that successful cup progress has regularly not been matched by league proficiency. "Last year, in December, they were not in the race for the title because they were already 20 points behind. This season, we have played five matches away in the Premier League - I know at difficult places to play difficult matches - but we have one victory and we have two defeats."
Refreshingly, Mourinho admitted that he may not have the right attitude amongst his players, suggesting that they were too "comfortable" at Stamford Bridge. Moreover, he admitted that he may have, simply, put the wrong team out. "I made 11 mistakes. I should have picked another 11 and not this one. It's the feeling I have. When my team plays so badly, it's the feeling I have."
The worry, from this end of the season ticket, is that Chelsea's next matches might offer more opportunities for banana skins: home next Wednesday to Schalke in the Champions League, home next Saturday to West Brom, managed by Mourinho's former No.2 at Chelsea, Steve Clarke, and then away matches to the uncompromising West Ham and then another European trip to Basel.
An Advent Day encounter with Southampton at Stamford Bridge seems a long way away for Chelsea fans, especially as the team embarks upon on the rickety-rackety rope bridge that is, traditionally, November.