**Persistent summer heat and urban heat island effects in Tokyo position nighttime lows near the long-term August average of ~24°C as the most probable outcome for August 14, 2026.** Official Japan Meteorological Agency forecasts and extended models currently indicate a minimum around 23–24°C under partly cloudy to overcast skies with scattered showers, consistent with the market’s leading 24°C (46%) and 23°C (28%) implied probabilities. High humidity and limited nocturnal radiative cooling—exacerbated by Tokyo’s dense urban environment—typically prevent sharper drops, while any increase in cloud cover or light rain can suppress temperatures toward the lower end of that range. Broader seasonal signals of above-normal warmth across Japan have not overridden these near-term patterns, keeping lower outcomes like 22°C or below at low single-digit probabilities. Updated JMA and numerical model guidance over the next 24–48 hours will be the key driver for any shifts in trader positioning ahead of resolution.