Bunny Park

This achievement is real life date related.

You can check your current season by checking the in-game store and selecting the lowest icon, that is where the seasonal stuff is located. If winter is not your current season, you either have to wait for it in real life OR go to Xbox Settings > General > Network settings > Press "Go offline". Then restart console and go to Settings > System > Time > Set date to first of January, year does not matter.

As a sidenote, you might want to unlock this one at the same time (buy any winter decoration):

Make sure to close the game and start it again.
Select "New game". Check that winter is activated by checking the store. If it says "Winter Wonderland", buy "Winter Hat" for 250 coins. Put it near a bunny and they will wear it eventually.

Once you have done this, you are free to change the clock again and go for the other date related achievements or of you want to unlock the achievement right away, close the game, go back to Xbox Settings > General > Network settings > Press "Go online" and start the game. It could take a moment to pop or if that does not happen, check your achievements, it might already be unlocked.