The game will resume during the Giants' next trip to Denver, which is Sept. 1-3.
Colorado's Wilin Rosario singled to lead off the second and advanced to third on back-to-back groundouts. Following a walk, Michael Cuddyer hit an infield single to the right of shortstop Brandon Crawford, whose throw didn't reach first, giving the Rockies an early 1-0 lead.
After the first rain delay, which lasted an hour and 22 minutes, the Giants' bats came alive in the fourth.
Hunter Pence smacked an 0-2 slider from Tommy Kahnle over the right-field fence to tie the game at 1-1. Michael Morse later drew a two-out walk and came around to score on a Pablo Sandoval double to center.
David Huff, who took over for Giants starter Tim Hudson after the stoppage, escaped a bases-loaded jam in the fourth after Justin Morneau popped out to catcher Buster Posey in foul territory to end the threat.
Nolan Arenado and Corey Dickerson both singled to right to put runners on the corners to start Colorado's half of the fifth. Rosario then grounded into a double play to tie the game at 2-2.
The game will resume with Cuddyer on first base with two outs in the bottom of the sixth.