National Weather Service forecasts indicate Atlanta’s overnight low into September 21 will hold near 70–72 °F under a lingering warm, humid air mass with light winds and only isolated afternoon thunderstorm chances. This setup keeps the daily minimum well above the 65 °F threshold while falling short of the 84 °F mark, aligning with the near-even market split between those two leading outcomes. A weak frontal boundary approaching from the north is expected to arrive only mid-week, delaying any meaningful cool-air advection until after the 21st. Historical September climatology shows typical overnight lows around 64 °F, underscoring how the current anomalously warm pattern supports the elevated probabilities traders have assigned to the middle temperature bins. Updated model guidance and evening observations will provide the next key signals before the market resolves.