The Legendary Pokémon Kyogre and Groudon have officially returned to Pokémon GO Raid Battles alongside Rayquaza for a limited time. According to the development team at Niantic, the hatching of Pokémon Eggs is now influenced based on which of the three Legendary Pokémon is defeated. If Rayquaza is defeated more than Kyogre and Groudon combined, Pokémon that typically prefer windy weather (for example, Bagon) are more likely to hatch from Eggs from March 5 to March 16. If not, Pokémon that prefer sunny or rainy weather (like Trapinch or Lotad) are more likely to hatch.
Pokémon GO Eggs now influenced based on which of the three weather trio Legendaries is defeated; Rayquaza hatches Pokémon that prefer windy weather
Pokémon Blog 
4 thoughts on “Pokémon GO Eggs now influenced based on which of the three weather trio Legendaries is defeated; Rayquaza hatches Pokémon that prefer windy weather”