I have been on the pitch to coach when it was turf, and on it as grass.
the pitch now is very good, I agree. But to suggest that rainfall is unlikely is completely contrary to facts and history. Mud Bowl? Fog Bowl ( look them up, they refer to classic CFL games in Toronto that weather severely affected). Perhaps it never rains in Southern California but historically it has in Toronto in September October and November.
Question: does the CFL season include those months or only the July and August whose drier weather you quote? We know they include MLS games.