I'm not going to remember all the traditions for every holiday, but this is what my calendar looks like since I moved to 28 days per season.
Last day of winter is New Year's Eve. Drinking, Party Spirit, Countdown to Midnight and Fireworks.
First day of spring is New Year's Day. It has Make Resolutions for sure, and maybe Be Thankful. Can't remember what else.
Middle of the first week of spring is Love Day. I didn't change it much from what the game came with.
Second Sunday of spring is Blossomfest, the day of the Flower Bunny and the egg hunts, with a religious ceremony. Grand Meal is generally a breakfast or a ham dinner. Used to have baking but it irritates me that eating the baked goods doesn't fill the tradition the way the grilled food does.
Middle of the third week of spring is Fool's Day. I always try to delete the popup holidays and stick with planned ones, so this is basically a regularly scheduled Prank Day.
Last week of spring we have Parent's Day. kind of Mother's and Father's day together. Give Flowers is a tradition, and I believe I put Travel, so my sims can go visit their parents, or take them out for dinner if they still live with them. I might have put in the Art and Music spirit so children would make crafts for their parents, but I can't remember for sure.
Summer starts with the 4th of Memorial, on the first Monday. There's Remembrance, Fireworks, Grilling and Drinking.
The weekend in the middle of summer is Summer Break/Vacation and the tradition is traveling. My sims usually schedule their vacations to include those two days.
Summer ends with Summer's End, which has Water fun, Fires, Grilling and Drinking.
In the middle of the first week of fall is Creative Day, which includes Art & music spirit, Baking and Gardening. No connection to real holidays, just wanted something to fill out the calendar.
Friday of the second week of fall is All Spook's Eve, with costumes, trick or treat, party spirit and mischief spirit. The next day is Day of the Departed, with Remembrance and Spooky Spirit.
Sometime the third week of fall is Anniversary Day, which involves giving gifts and going out. No matter when they got married, their anniversary is in the fall.
Last Thursday of fall is Harvestfest, without the gnomes.
First week of Winter ends with Winterfest Eve and Winterfest. I think they're Friday and Saturday. Winterfest Eve has Father Winter and Decorating, while Winterfest proper has the Grand Meal and gift giving and receiving. One of them may have the religious ceremony.
The following week has Boxing Day I think on Monday, with the traditions of fighting and exercising because I'm into bad puns.
The third Sunday of winter is Big Game Day, with watching sports, playing games, party spirit, having company and drinking.
Later that third week I have Cabin Fever Day, which involves traveling and the polar plunge. For sims who can't stand being inside anymore.
Either the last Sunday of winter or the day before, I have the Holiday of Lights, which is mostly just about lighting the menorah or kinara.
And then we're back at New Year's Eve.
