Niantic has announced that the spring 2021 Season of Legends will run from Monday, March 1st, 2021, at 8:00 a.m. to Tuesday, June 1st, 2021, at 10:00 a.m. local time!

The Season of Legends starts soon!

Trainers, During the Season of Celebration, we got to explore and celebrate regions of the Pokémon world, all leading up to Pokémon GO Tour: Kanto! Now, we’re excited to announce the next Season: the Season of Legends!

From Legendary Pokémon to legendary Trainers, this Season will celebrate legends in Pokémon GO. The Season of Legends will run from Monday, March 1, 2021, at 8:00 a.m. to Tuesday, June 1, 2021, at 10:00 a.m. local time! Read on for an overview of what you can expect during this Season, and look out for a detailed blog once the Season starts.

More Pokémon will make their Pokémon GO debut in Legendary Raids and Mega Raids!
This Season will start with some Legendary Pokémon making their Pokémon GO debut—Therian Forme Tornadus, Therian Forme Thundurus, and Therian Forme Landorus! Stay tuned for more details. There might be some other Legendary faces making their Pokémon GO debut appearing later in the Season, too!

Starting March 1, different Mega-Evolved Pokémon will be appearing in Mega Raids, and other Mega-Evolved Pokémon will be making their Pokémon GO debut over the course of the Season. Keep an ear out for more details soon, Trainers!

Different Pokémon will be appearing in the wild!
As the seasons change, different kinds of Pokémon will be appearing in different habitats in the wild! For example, you might find Mantine or Frillish appearing near water, or maybe you’ll happen upon a Voltorb or Glameow while in the city! If you happen to be traversing near grassy and forested areas, you might find Hoppip floating peacefully in the air. These and many more Pokémon will be appearing more often in the wild, so keep a lookout and stay tuned for more details!

Hemisphere-exclusive Pokémon
During this Season, the kinds of Pokémon that appear more often in the wild exclusively in either the northern or southern hemisphere will be greatly expanded from last Season!

In the northern hemisphere, you’ll be able to encounter Pokémon like Tangela, Combee, Croagunk, Ducklett, and many more in the wild! First partner Pokémon originally discovered in the Sinnoh region—Turtwig, Chimchar, and Piplup—will also be appearing in the wild, alongside Spring Form Deerling. If you’re extremely lucky, you might even encounter Pokémon such as Scyther, Dratini, or Cottonee in the wild! In the southern hemisphere, Pokémon like Mankey, Yanma, Buizel, Woobat, and many more will be appearing in the wild, alongside first partner Pokémon originally discovered in the Unova region—Snivy, Tepig, and Oshawott! If you’re extremely lucky, you might encounter a Pineco, Bagon, or Ferroseed. Keep your eyes out for Autumn Form Deerling, too!

Different Pokémon will be hatching from Eggs!
Pokémon like Treecko, Torchic, Mudkip, Budew, and more will be hatching from 2 km Eggs. Drowzee, Azurill, and Munna will be hatching from 5 km Eggs, and intrepid Trainers might find Nincada, Alomomola, and more hatching from 10 km Eggs! Stay tuned for more details.

Season-exclusive Special Research
Toward the start of the season, all Trainers will be able to access the Season of Legends Special Research. Follow Professor Willow as he makes exciting discoveries about Therian Forme Tornadus, Therian Forme Thundurus, and Therian Forme Landorus, the first three Legendary Pokémon featured during this Season. Complete this Special Research to earn Tornadus, Thundurus, and Landorus Candy as well as other rewards.

Be on the lookout for bonuses and items throughout the Season!
You can look forward to even more goodies this Season, such as the following bonuses and items.

• Players can receive increased XP from five-star raids throughout this Season only.
• Free Remote Raid Passes will be available at certain times during the Season. Stay tuned for more details on when these Remote Raid Passes will be available in the shop!

Throughout the Season, you’ll have even more opportunities to be legendary! March Community Day, GO Battle League Season 7, all-new events, and more will be coming. You can also look forward to a series of events toward the end of the Season that will certainly be legendary.

Please be aware of your surroundings and follow guidelines from local health authorities when playing Pokémon GO. Upcoming events are subject to change.

Source: https://pokemongolive.com/post/season-of-legends-2021/?hl=en