"The Season 2 premiere of “Outlander” equaled the show’s best same-day 18-49 rating ever and set a new high in viewers. The show opened with a 0.4 in the demo for Starz — tying the mark for the last episode of Season 1a in September 2014 — and scored 1.46 million viewers, its best number ever" (Source)
For comparison, under the cut is the chart with all of the figures for Season 1.
[Season 1 Ratings]
Note that these numbers do not reflect StarzPlay viewings, the Starz/Amazon apps, or early On-Demand viewings. We won't know total viewership unless Starz decides to release it.
Also of note, Starz's highest rated series is Power, but their highest rated episode was the most recent finale with 1.54 million viewers, not at all out of reach for Outlander.
KAY WHERE IS OUR SEASON 3 ANNOUNCEMENT, STARZ?