**Forecast consensus from the National Weather Service and multiple models centers the overnight low for September 18 near 64–65 °F, aligning with the market’s highest-implied probability (47.5%).** This range matches the typical pre-dawn minimum under the current marine-influenced pattern, where a weak onshore flow and lingering marine layer moderate temperatures without strong radiational cooling. Recent observations reinforce this outlook. Nighttime lows at Los Angeles International Airport and downtown stations have held in the mid- to upper 60s through mid-September, with September 15–16 minima near 68–69 °F and no sharp cooling trend. Ensemble guidance shows limited spread for the 17–19 September period, keeping the expected minimum within a narrow 62–66 °F envelope and assigning only modest probability to excursions above 66 °F or below 62 °F. Key resolution factors include the official 24-hour minimum recorded at the primary Los Angeles station; clear or mostly clear conditions and light winds overnight favor values at the lower end of the forecast range, while any increase in cloud cover or onshore breeze could nudge readings slightly higher. With resolution imminent and model agreement high, trader positioning reflects the narrow uncertainty band around the 64–65 °F outcome.