**An incoming Pacific low-pressure system and associated frontal passage are the dominant drivers keeping Seattle's overnight low on September 2 centered in the mid-50s °F.** Official and model guidance from the National Weather Service and private forecasters converge on a low in the lower-to-mid 50s (roughly 53–58 °F), consistent with the historical average low of 55.1 °F for the date. South-to-southwest flow ahead of the front supplies mild marine air, while widespread cloud cover and periods of rain suppress radiative cooling that would otherwise allow deeper nighttime drops. The closely matched market probabilities for the 54–55 °F, 56–57 °F, and 58–59 °F bins reflect modest uncertainty in exact minimum timing and localized cooling under variable rainfall. Stronger southerly winds and heavier precipitation tend to hold temperatures near 56–58 °F, whereas brief clearing or lighter winds could allow a dip into the mid-50s. No Arctic or interior cold-air intrusion is forecast, keeping the risk of sub-50 °F readings low and the chance of 60 °F+ minimal. Updated model runs and National Weather Service briefings through the morning of September 2 will be the key near-term catalysts for any shifts in trader positioning.