Current forecasts from the National Weather Service and ensemble models indicate Seattle highs on September 5 will likely fall in the mid-60s to low-70s Fahrenheit, driven by persistent marine layer clouds, light onshore flow from the Pacific, and residual moisture from recent showers that limit daytime heating. Historical September averages near 73°F provide a baseline, yet the current pattern of variable cloud cover and weak high pressure favors values clustered around 67–71°F. Model spread remains notable due to timing of any clearing or onshore breeze shifts, with NWS updates and new runs expected before resolution. Trader-implied probabilities reflect this genuine forecast uncertainty across the central bins rather than strong consensus on any single outcome.