Monster Hunter: World's first year was filled with weekly quests, special crossovers, and big, special events like the siege of Kulve Taroth and the anniversary Appreciation Fest. The PC version has gotten those events in a compressed timeframe, and there are more still to come in 2019 as we lead up to the release of Iceborne, Monster Hunter World's first expansion, sometime this year.
Here's the calendar of all the MHW events we know about for 2019. As more events, fests, monsters, and game patches are announced, we'll add them here. (Keep in mind we aren't listing events that have already run on PC, but those will be back during the seasonal fests).
Events that have already happened on consoles are listed without dates in the order they originally released, since they're likely coming to PC—we just won't know exactly when until Capcom says the word.
Monster Hunter: World event schedule for 2019
The Eye of the Storm
Monster: Arch Tempered Kushala Daora | PC date: February 22 - 28
The Arch Tempered version of Kushala Daora is around for a week. Taking down the elder dragon will net you tickets to craft the Kushala Daora Gamma armor and Guild Cross Layered Armor.
When Blue Dust Surpasses Red Lust
Monster: Arch Tempered Lunastra | PC date: March 8 - March 21
As if Lunastra wasn't already difficult enough to fight! AT Lunastra will be a hell of a battle, and was first available on consoles in October. This fight will net you tickets to craft the Lunastra Gamma armor. Note: On consoles, this event also offered tickets to earn the Sakura layered armor (as in Street Fighter's Sakura). It looks like that isn't the case for PC.
Monster: Arch Tempered Zorah Magdaros | PC date: TBA
Have fun with the most boring, drawn out encounter in Monster Hunter World, against the giant elder dragon Zorah Magdaros, now with more health! Get Zorah tickets to craft the Zorah Gamma Magdaros armor.
Like a Moth to the Flame
Monster: Arch Tempered Xeno'jiiva | PC date: TBA
The big bad version of MHW's campaign finale, with all new rewards! Beat this jumbo baby dragon to earn Xeno'jiiva tickets to craft the Xeno'jiiva Gamma armor set, and the Commission layered armor.
SDF: Silent, Deadly and Fierce
Monster: Odogaron, Deviljho, Lunastra | PC date: TBA
Monster Hunter's console crossover with Ubisoft's Assassin's Creed awarded an item called Senu's feather, which could be used to craft the Assassin's Hood Mantle and Bayek layered armor. All you have to do is fight the three most aggressive monsters in the game in an arena! Possible this never comes to PC, but fingers crossed.
The Fury of El Dorado
Monster: Arch Tempered Kulve Taroth | PC date: TBA
The roided-up version of the Kulve Taroth siege ran on consoles for most of January and February, so it's likely a bit down the road for PC players.
Contract: Woodland Spirit
Monster: Leshen | PC date: TBA
MHW's Witcher crossover, starring none other than Geralt of Rivia himself. Ciri's here too, and the fight against the Leshen, a Witcher monster, is meant to be on par with Extreme Behemoth, the toughest in the game so far. Take down the Leshen to craft the Witcher's Silver Sword (sword and shield), Zireal (dual blades), Geralt layered armor, Ciri Alpha armor, and Ciri layered armor.
If the schedule remains identical to consoles, this event won't happen for many months, but given The Witcher's PC heritage, we may see it sooner rather than later.
Monster Hunter: World seasonal fests for 2019
If MHW repeats the event fests of 2018, we can look forward to the following seasonal festivals this year. During fests, all previous event quests return and are available for a few weeks, making them a good time to catch up on those special bits of gear and layered armor you missed the first time. They also have their own unique items to collect. What we don't know is how the Iceborne expansion will affect the seasonal fests, if at all.
Spring Blossom fest
2018 dates: April 6 - 20
Summer Twilight fest
2018 dates: July 13 - 27
Autumn Harvest fest
2018 dates: September 21 - October 5 (consoles)
Winter Star fest
2018 dates: November 30 - December 18
Console events that may not come to PC
Down the Dark, Muddy Path
Monster: Barroth | PC date: TBA
The first PS4-only Street Fighter quest, an arena fight against low rank Barroth. It awards the SFV tickets used to craft the low rank Ryu armor set. It happened in February 2018 on consoles and has yet to make it to PC, indicating that it might not ever make the leap.
The Awakened Satsui No Hado I, II, and III
Monster: Nergigante | PC date: TBA
This PS4-only arena quest is a Street Fighter crossover that rewards SFV Ticket IIIs, to craft the Ryu Alpha armor. It happened in May 2018 and has yet to make it to PC, indicating that it might never make the leap.
Empress in Full Bloom I, II, and III
Monster: Pink Rathain | PC date: TBA
These arena fights on the console version rewarded SFV Ticket II items used to craft the Sakura Alpha armor set. Unknown if/when they're coming to PC, but considering Street Fighter is also on Steam, it seems likely.