Seattle's July 17 high temperature market centers on near-term forecast guidance from models and agencies like the National Weather Service, which currently converge on a most likely peak near 75°F amid typical mid-summer maritime conditions. Persistent onshore flow from the Pacific and a moderating marine layer often suppress afternoon warming in the Puget Sound region, keeping daily maxima in the mid-70s even during warmer-than-average seasonal patterns. Minor variations in cloud cover timing, wind strength, or subsidence under high pressure can shift the outcome by a degree or two, creating tight implied probabilities between the 74–75°F and 76–77°F bins. Historical July averages near 76–79°F provide context, yet short-range model updates through tomorrow morning remain the key catalyst for any late shifts in trader positioning.