Official observations from Los Angeles International Airport and National Weather Service stations confirm a daily maximum of 78–79°F on September 13, 2026, aligning with the market’s near-certain resolution. Mid-September climatology for coastal Los Angeles features marine-layer stratus and onshore flow that typically caps highs in the mid-to-upper 70s, matching historical averages near 76°F and suppressing offshore warming. Absent any Santa Ana wind event or anomalous high-pressure ridge, temperatures remained within the narrow two-degree band. Traders priced the outcome at 100% once preliminary climate data and hourly readings eliminated adjacent ranges, reflecting the tight resolution criteria and low forecast uncertainty once the day concluded.