**With roughly 1.0 inch recorded through mid-September—slightly above the long-term average pace—trader sentiment centers on whether the second half delivers enough additional rainfall to reach 1–1.5 inches or stays drier.** Seattle’s September climatology features a transition from summer dryness (historical average ~1.6 inches) to increasing autumn storm activity, driven by strengthening onshore flow and the jet stream. Current National Weather Service guidance and ensemble models indicate persistent high pressure, northerly winds, and minimal precipitation chances (mostly 0–10%) through at least September 22, supporting the tight contest between sub-1-inch and 1–1.5-inch bins. Late-month model runs and any shift in Pacific moisture patterns remain the key variables that could tip totals higher or keep them below the seasonal norm.