Recent National Weather Service and model guidance indicates partly sunny skies over Seattle on September 1 with highs most likely in the low to mid 70s under a building ridge that limits marine layer intrusion. This setup aligns closely with the 1991–2020 climatological average high of roughly 74°F while keeping temperatures below late-summer peaks. Cloud-cover timing, southerly flow, and any residual low-level moisture remain the key variables that could shift the daily maximum by a degree or two across forecast runs. With multiple bins clustered near the expected range, traders are weighing small differences in afternoon insolation and boundary-layer mixing against the risk of earlier stratus or a quicker marine push that would favor the lower bins.