When does the "Christmas season" start?

Depends on whether I host Thanksgiving or not. On the years that it is our turn, I don't decorate until after Thanksgiving (RIGHT after Thanksgiving as on Black Friday!). On the years that we don't host Thanksgiving, I usually will start to decorate in November but still not put the tree up until after Thanksgiving.

As far as everything except decorating, I have followed the "Holiday Grand Plan" for years so I start shopping, cleaning, and planning for Thanksgiving/Christmas the last week in August! This is my favorite time of the year.

The day after Thanksgiving. 

I've never experienced a cold Christmas so I don't have anything to compare to but Summer Christmas is amazing. Not many places here will be that hot on Christmas Day (although I have experienced quite a few) the temps are often in the 70-80 range. Being able to hold large gatherings outside where most houses are built for outdoor undercover entertaining, swim in the pool or go to the beach, kids running under the sprinklers, cold champagne and prawns, sitting outside in balmy temperatures until late at night. Its fantastic  

I was in college and one of my classmates (from Florida) informed me that their Christmas Eve tradition was to go water-skiing. Mind blown 🤯 in the best way possible.

I used to never put up any Christmas decor until after Thanksgiving. But I was always frustrated because it seemed like by the time I got everything done and tubs, etc cleaned up, it was almost Christmas with little time to really enjoy it.
2 years ago, I went to visit my son in Colorado over Thanksgiving, and I decided to do all my decorating before I left. I knew I would be tired after the drive and hiking in the mountains. LOL It was so nice coming home and having everything done and cleaned up.

Last year, I decorated earlier than ever. I bought a new tree the first weekend in November and decided to put it up right away. Then, I figured I might as well do all the rest of my decorating, too. I was finished well before Thanksgiving, and I loved it. I hate this time of year when it gets dark so early, and I love having my Christmas lights on at night. I do not however, turn on any outside lights until after Thanksgiving.

This year, I have my tree up, but nothing else. I will be doing everything else this weekend though. I do love Thanksgiving; it's actually one of my favorite holidays. But I think I can be just as thankful while enjoying my Christmas decorations. LOL

This year, I am going to dinner at my daughter's house (the one who just got married). I'm pretty sure she will have her tree up, too.

I always say, do what makes you happy. If that is putting up your tree right after Halloween, so what?

In my mind, it starts the day after Halloween.   Though I don't start putting up decorations until after Thanksgiving.

In my house, Christmas was banned until after Thanksgiving. I wanted to teach my kids that we had to show thanks for all we had before we headed into presents. I tried to downplay the gift part and focus on the joy and magic part so I decorated the daylights out of my house and we did holiday stuff. Now that DH and I are retired and the kids are gone, there's less of a hard line. I don't have the energy to do it all in a couple of days, so decorating starts now.

I also work on a Holiday Home Tour for charity and we've been planning since last January, so Christmas is pretty much on my mind all the time.

In my household, Christmas season starts after Thanksgiving, which is my favorite holiday (food, family, football). I don't have to "do" Thanksgiving anymore, my oldest daughter has taken over all the duties including hosting, so I just go and enjoy the festivities! Usually I'm too tired to start decorating after dinner, so wait until Black Friday to start. I do celebrate Advent, including lighting the candles, so need to be ready before that.

A few years ago (probably during COVID) I bought a pencil tree, and put it up right away. It's in my dining room year-round with white lights on it. Sometimes I add other colors - right now it has orange, green and purple lights for Halloween. It gives just enough light to brighten up the space so I can see my way without turning on all the lights. I have it on a timer so it comes on at dusk and goes off around midnight. I love the look of soft lights and will always have it up now.

As someone who has experienced both warm and cold Christmases, cold wins hands down. As fun as it is to swim in a pool on Christmas Day, it’s not nearly as hygge as sitting by a fireplace with snow falling outside.

We put up lights on a good weather day because nothing sucks as hard as being frozen on top of a ladder. Any decorating we do it primarily the weekend after Thanksgiving. That said, I'm ready to burn a tree scented candle and listen to some Nat King Cole now.