Recent National Weather Service guidance and supporting ensemble models place Seattle’s daily high near 58–59 °F at Seattle-Tacoma International Airport, reflecting the region’s typical springtime maritime influence from cool onshore flow off the Pacific that moderates daytime warming. This consensus aligns with climatological norms for mid-May, when average highs hover around 67 °F but frequently dip lower under persistent marine layers. Traders have priced the 58–59 °F bin at 99.7 % because only modest deviations from current trends—such as a stronger-than-expected offshore wind shift or a late-day clearing that allows additional solar heating—could realistically push readings into the 60–61 °F range before the official observation period closes.