Latos (7-13) broke a personal four-start winless streak, holding the Rockies to two runs on five hits and a walk over seven frames. He struck out eight as San Diego avoided a three-game sweep.
Venable capped the scoring with a three-run triple in the eighth inning and Jeremy Hermida added three RBI with two singles for the Padres.
Colorado's Aaron Cook (3-9) coughed up three runs on four hits over six innings.
Dexter Fowler went 3-for-4 with a run scored and Seth Smith added an RBI single for the Rockies.