Brandon Belt went 3-for-3 with a two-run hit ball to lift the 0, in the second meeting of a season-ending three- game series.
Bumgarner (13-13) struck out nine and did not issue a walk to end his .500 campaign on a winning note.
"It's good to play well this last series," said Giants manager Bruce Bochy. "We're out of it but the guys continue to play well and they're trying to reciprocate their appreciation to the fans."
Conor Gillaspie added a two-run, inside-the-park homer for San Francisco, which won the opener of the set, 3-1.
Alex White (2-4) surrendered three runs on six hits in a four-inning start for Colorado, which has lost 11 of its last 13.
"Any time a manager is walking out there in the third or fourth inning of a game, or after four innings you don't see a starter return, the chances of winning that game are not too good," Rockies manager Jim Tracy said.
The only two hits the Rockies managed off Bumgarner came in the second, as Kevin Kouzmanoff led off with a double and moved to third on Jordan Pacheco's single. Bumgarner settled though, striking out the side to escape the jam.
Andres Torres led off the home first with a walk, moved to second and third on a pair of wild pitches and scored on Mike Fontenot's sacrifice fly.
Belt's two-run shot into McCovey Cove in the fourth added to the lead, and the Giants pushed two more across against Esmil Rogers in the sixth. Belt led off the frame with a walk and scored on a triple by Brandon Crawford, who eventually crossed the plate on a wild pitch.
Bumgarner eclipsed the 200-inning plateau in his first full season in the big leagues...The Giants went 1-for-10 with runners in scoring position...The Rockies did not have a runner reach past first base after the second frame...Gillaspie's homer was the first of his career.