Current forecast guidance from the National Weather Service and ensemble models points to a Seattle high near 62°F on May 17, driven by persistent onshore flow from the cool Pacific that caps daytime heating in the city’s maritime climate. This pattern keeps the market split between the 64°F-or-higher outcome at 43.5% and the 62-63°F bin at 34.5%, with lower ranges trailing. Slight differences in model runs hinge on the precise strength and timing of afternoon sea breezes, cloud cover breaks, and boundary-layer mixing, which can add or subtract a degree or two from the peak reading at Sea-Tac. Historical mid-May averages of 64–66°F provide context, yet today’s stable synoptic setup favors the tighter 60–63°F cluster unless a stronger ridge builds unexpectedly.