Nobody knows, but during the Tyranitar Community Day, Tyranitar raids were no more common than they usually are.
Up
0
Down
Good point. The three hour period on Saturday for Articuno is not a community day, but that is the closest analogy.
Up
0
Down
You would think that Niantic would make it easy for us to do a lot of Articuno raids at once, but they probably won't change the rate of T5 eggs. Hopefully they discontinue Regice for those 3 hours or it will really suck.
Up
0
Down
My prediction is that Niantic will not change the rate of T5 eggs, but Articuno will be the exclusive T5 hatch (other than EX Raid Mew Two hatches) during the 3 hour period.