Fall
- The grass and trees gradually changing colors throughout the season.
- Maple Leaf Season, spanning from November 15th-26th in the Northern Hemisphere or May 16th-25th in the Southern Hemisphere. Maple leaves float through the air which you can catch with your net, basically the same idea as the Cherry Blossoms in Spring. These leaves can be used in DIY recipes.
- You can collect acorns and pine cones by shaking trees. These can be used in DIY recipes. Acorns are collected from hardwood trees, while pine cones are collected from cedar trees.
- A Halloween event. Throughout October you can purchase one candy per day, per character, from Timmy & Tommy. These candies should be kept up until Halloween day where you can give them to your residents who will be out Trick or Treating in their costumes. If you get Lollipops from your residents during this process, consider giving some to Jack since they're his favorite and he'll give you stuff like Jack's head and Jack's robe so you can dress up like him.
You can collect most of the Spooky DIYs from your villagers throughout the month of October if you see them in their house standing at their workbench. However, you can only acquire some of these DIYs on the day of Halloween itself: the Spooky Flooring, Spooky Rug, Spooky Wall, Spooky Garland, and Spooky Table Setting can only be acquired by giving candy to your villagers on Halloween during the trick or treat hours, and you can only get the Spooky Carriage and the Spooky Wand by giving 3 Lollipops to Jack.
All of the Spooky DIYs utilize the pumpkins you can grow from the seeds you buy from Lief. You can also use the different colors of pumpkins to get different customizations of them with different colors and facial expressions.
Also, since I mentioned that your villagers will be in costume on Halloween, you yourself can purchase various costume items from the Able Sisters' shop throughout the month of October.
- A Turkey Day/Thanksgiving event wherein you collect ingredients to help Franklin the turkey cook up some food for the residents. This can include fish, deep sea creatures, manilla clams from the beach, fruit, pumpkins, and/or mushrooms. You can find out what ingredients you need by fulfilling tasks/trading stuff with whichever of your villagers are in their houses. You earn Turkey Day DIYs by helping Franklin make these meals.
- Various types of mushrooms which can be collected and use in DIY recipes and which can also be used in Turkey Day recipes. Mushrooms are only available in the month of November in the Northern Hemisphere or May in the Southern Hemisphere.
Winter
- Snow begins falling on December 9th, then the island will be completely covered in snow on December 10th and will remain that way until near the end of February.
- Similar to the Cherry Blossoms in Spring and the Maple Leaves in Fall, Winter has snowflakes which you can catch with your net that can be used in recipes.
- When walking around the island once it's covered in snow, you will find snowballs. You can push them around to increase their size and/or to move them around. You put the two snowballs together and you will form a snowman, though in New Horizons they only have Snowboys (New Leaf featured Snowman, Snowmam, Snowboy, and Snowtyke). If you construct the Snowboy from snowballs that are the correct size, he will give you a DIY recipe. On the days after he's built, up until the day he melts three days later, he will give you a Large Snowflake which can be used in the DIY recipes he teaches you. However, if you don't have the snowballs the correct sizes when you build him, he'll just remark that he could've been built better and won't give you anything.
- Similar to the acorns and pinecones in Fall, starting on December 15th, you can collect red, blue, and yellow decorations from trees which are used in Toy Day/Christmas DIY recipes. These can only be collected from cedar trees, and you'll be able to tell visually because the trees you collect them from will have Christmas lights on them.
- As you could guess from the above, a Toy Day/Christmas event. Rather than December 25th, though, it instead takes place on December 24th. Jingle the reindeer will give you his sack of gifts and task you with delivering presents to your residents.
- A New Year's Eve countdown event. You can get a glow wand and New Year's hats, the stock of which changes by the year. There will be a big countdown timer in the Resident Services plaza where Tom Nook, Isabelle, and most of your residents will gather.
