**Forecast consensus points to an overnight low in the low 70s°F for Atlanta on September 18, 2026, aligning with the market’s highest-implied probabilities on the 72-73°F and 74-75°F buckets.** Official National Weather Service guidance and multiple model runs issued September 17 project a low near 71–73°F under a strong upper-level ridge that has maintained unseasonably warm conditions across the Southeast. Light winds, partly cloudy skies, and a warm air mass limit radiational cooling, keeping minimum temperatures well above the late-September climatological average of roughly 64–65°F. This setup explains the strong trader preference for the 72–73°F range at 53% implied probability, with 74–75°F at 30% capturing minor upside variance from localized heat retention or slight forecast adjustments. Lower-probability buckets for much cooler readings (e.g., 63°F or below) reflect the low likelihood of any significant cold-air intrusion or clear-sky cooling before the next frontal influence arrives over the weekend. Warmer extremes remain possible only if daytime heating lingers longer than expected, but current model consensus and NWS point forecasts favor the narrow low-70s window. Updated model runs and the evening NWS forecast discussion on September 17–18 will provide the next key data points for any shifts in these market-implied odds.