Traders see 70-73°F as the most likely minimum for New York City on August 20 because National Weather Service guidance and ensemble models indicate overnight lows near 70°F under partly cloudy skies with light winds. This range reflects typical late-summer radiational cooling moderated by residual humidity and urban heat island effects, consistent with the month’s warmer-than-average pattern. Differentiation between 70-71°F and 72-73°F hinges on the exact timing of any clearing, dew-point depression, and boundary-layer mixing overnight, factors that short-range models still show modest spread. With resolution imminent, fresh model runs and surface observations will determine whether the minimum settles at the lower or upper end of that narrow band.