Assassin's Creed Valhalla celebrates the first day of Spring—the vernal equinox—with the Ostara Season free update. Back at your home base, Ravensthorpe, you have springy decor and familiar activities. There will also be new quests, cosmetics, and settlement decorations with a "springtime twist" starting March 18 and going until April 8. Not to mention something special within the Godly Reward, a bundle of Yule Gear and Opals.
You hunt for colored eggs, shoot some arrows, drink until you're tipsy, and throw some friendly punches. At night, you'll defend Raven Clan from wild spirits running through the forest. Put some flowers in your beard while you do it. You might even do it in Altair's outfit (from the first Assassin's Creed). You'll have to complete at least one story arc to access the event: either Grantebridgescire or Ledecestrescire.
Up further along on the road map is Wrath of the Druids, Valhalla's first expansion, available April 29. And, coming late Spring, is the free game mode, Mastery Challenge.