Trader consensus on an 68–69°F high for Seattle on September 22, 2026, reflects official NOAA observations at Seattle-Tacoma International Airport matching that exact range amid typical late-September marine-layer conditions. Persistent onshore flow, morning stratus, and dew points in the low-to-mid 50s suppressed afternoon heating, keeping maxima near the 1991–2020 daily normal of 68.6°F. Ensemble guidance and National Weather Service point forecasts converged on this narrow band days in advance, with light winds under 10 mph limiting mixing and any brief clearing. Only a substantial reduction in cloud cover or an unexpected offshore shift could have pushed readings into the 70s, scenarios that did not materialize.