The five shutouts are tied for the most in a season by an American League pitcher since 1989, joining Bert Blyleven ('89), Roger Clemens ('92) and David Wells ('98).
Hernandez joins Mark Langston (September 1988) as the only pitcher in Mariners history with three shutouts in one calendar month.
Only two other pitchers in Major League history have had three 1-0 shutouts in a calendar month: Carl Hubbell for the Giants (July 1933) and the Braves' Dick Rudolph (August 1916).
Hernandez is the first Major League pitcher since Randy Johnson in 1998 with the Astros to record five shutouts in a 12-start span.
The right-hander's 16 starts of seven-plus innings with one or fewer runs is a Mariners record, breaking the mark of 15 he set during his 2010 Cy Young Award season.
Going into Tuesday's games, he had the lowest ERA in the Major Leagues (2.43), the most innings pitched (196 2/3), was third in strikeouts (184) and sixth in batting average against (.218).
Hernandez's ERA since June 17 is 1.40 over a span of 14 starts. The next closest in the Majors in that time frame: Tampa Bay's David Price at 2.09.
The Mariners know what they've got.
"His stuff is unbelievable," said first baseman Justin Smoak. "When he's on, he's on. And when he's off, he's still good. It's just fun to play behind him."
Manager Eric Wedge said it's as good a run as he's seen by a pitcher.
"In the beginning of '08 with Cliff Lee, he got off to an incredible start for us [in Cleveland] with some ridiculous numbers," Wedge said. "But in regard to just how dominant Felix has been in this stretch, I've never seen anything like it."