Recent National Weather Service forecasts for Seattle on August 13 indicate highs near 78–80°F under mostly sunny skies with light westerly flow and limited marine layer intrusion, driving the market's tight clustering around the 78–81°F bins. Persistent upper-level ridging has sustained above-average warmth across the Pacific Northwest this week, while ensemble model guidance shows modest spread due to variable onshore breeze strength that could cap or boost readings by 2–3°F. Historical August climatology centers near 77°F at Sea-Tac, so current conditions reflect a modest positive anomaly that traders weigh against the narrow resolution windows and potential for late-day clearing or cloud build-up.