Does the marine layer at Mariners' T-Mobile Park really suppress offense?

On vintage Seattle summer days, you won't find a better environment anywhere in America to take in a ballgame. No ballpark in Major League Baseball suppresses offense as much as T-Mobile Park. What's more: Through the first month of this season, offensive output in Seattle has reached a new low, with run production values at T-Mobile Park ranking dead last among all MLB venues. The scarcity of runs in Seattle over the past few years, in particular, has coincided with the rise of the Mariners pitching staff as one of the best in baseball, capable of shutting down any opposing lineup.