Niantic has changed the EX Raid system again. Yesterday’s wave of invitations was a steep departure of what was previously observed, and the same thing goes for the way EX raids were triggered. Unlike previous EX events, these ones were based around large Level 10 S2 cells.

We strongly advise reading our guide on S2 cells before you continue reading this article: A comprehensive guide to S2 cells and Pokémon GO. In a nutshell, a S2 cell is a developer friendly way to represent an area of the world that has a set size, location and unique identifier. S2 cells are used to approximate areas of the Earth without using coordinates, longitude and latitude.


Up to today, it was known that Niantic uses Level 12 S2 cells to determine if an EX Raid will take place in that area. Players would usually pick one gym per cell, make sure it was inside a park and raid the hell out of it in order to trigger an EX Raid.

Yesterday, we have received confirmation from our readers and Discord researchers that this raid cycle used Level 10 cells instead of Level 12 cells. As a result, EX raids were triggered, but they happened over larger areas and thus the number of potential triggers was reduced.

Here’s a comparison of the two types of cells (illustrated over Dalmatia, Croatia):

  • Level 10 cells are 81.07 kmin size (on average)
  • Level 12 cells are 5.07 kmin size (on average)
  • One S10 cell covers roughly the same area as sixteen S12 cells

Visual comparison of cells and our local efforts to trigger Mewtwo. Green dots mark gyms that are hosting an EX Raid, red dots mark the gyms local groups were trying to trigger:

Out of six S10 cells that cover our local play area, four are hosting an EX Raid. The case of Kastel Stafilic is especially interesting as it was not raided in recent months and is considered to be a dead zone.

As you can see from the picture above, most of the raid passes in the top right S10 cell have been spent in vain. The bottom right S10 cell is particularly interesting as the center of raiding attention was the gym that was not triggered as an EX raid host, despite it being heavily raided.

Does this mean that cell (and not gym) activity is the key factor in triggering an EX event? Time will tell, we are not ready to proclaim anything, especially with the randomness of this EX wave.

The same area covered in Level 12 cells, which were previously used to plan and execute EX triggering attempts. It was quite a chore.

Thoughts and parting words

Although this will be an unpopular opinion, we are onboard with Level 10 cells being used for EX Raids. The reduced number of cells leads to increased rarity and difficulty of obtaining a Mewtwo, but makes organization and triggering attempts easier.

If the switch from S12 => S10 cells is permanent (and we should know that as early as next week), it will force urban players to diversify their raiding area and it will make it easier for rural players to come together and complete EX Raids.

We are not sure how we feel about gyms giving out EX invites even if they haven’t been raided, but it could be a mechanism that Niantic put in place in order to help out lower activity areas.