Niantic has announced that to celebrate the second anniversary of Pokémon GO, from July 6th, 2018 until July 31st, 2018, Pikachu and Pichu will appear more often. A special summer style Pikachu dressed in a straw hat and sunglasses will appear throughout the month. 
Here is their post about this:
Trainers, Can you believe it’s already the second anniversary of Pokémon GO? Thank you so much for adventuring with us and catching Pokémon all over the world. You truly are what makes this journey so special!
None other than Pikachu has joined in to celebrate this momentous occasion, so keep an eye out for Pikachu and Pichu as they will appear more frequently tomorrow (July 6 PT) until July 31. Plus, this year, you can say hello throughout the month to a special “Summer Style” Pikachu, that’s decked out in a straw hat and sunglasses.
Can’t get enough Pikachu? Pikachu Fan Avatar items will be available for purchase! Trainers with a gold Pikachu Fan medal will be able to purchase all related items, which include a T-shirt and Pikachu ears.
We’ve heard so many amazing stories from Trainers, and we can’t wait for what’s on the horizon. We’re excited to announce that Special Research on the Mythical Pokémon Celebi will be available globally in the near future. So stay tuned, Trainers, and get out there and GO!
What do YOU think about this? Will you look for and catch those Pikachu? Be sure to let us know in the comments..