Seattle's highest temperature on August 15 is expected to fall in the upper 70s to low 80s°F based on National Weather Service guidance, aligning with trader emphasis on the 78-79°F and 80-81°F bins. Persistent marine air from Puget Sound typically moderates afternoon highs during mid-August, while a broader regional warm anomaly—marking Seattle's 14th consecutive hotter-than-average summer—supports probabilities above the long-term mean of roughly 77°F. Recent model runs show limited day-to-day variability, with light winds and mostly sunny conditions limiting further warming or cooling. Strengthening El Niño conditions in the tropical Pacific exert only subtle summer influence over the Northwest but contribute to the overall elevated baseline that keeps extreme outliers below 10% implied probability. Updated NWS briefings and morning model guidance on August 15 will provide the final inputs for market resolution.