Trader sentiment has locked onto 13°C as the highest temperature recorded in Milan on May 15, reflected in the 100% market-implied odds for that outcome. This consensus stems directly from official meteorological observations showing a daily maximum of exactly 13°C under a stable high-pressure regime with northerly airflow that suppressed daytime warming. Mid-May climatological baselines for the Po Valley typically reach 18–22°C, so the cooler reading represents a clear departure driven by persistent cloud cover and lower-than-normal solar insolation. Resolution criteria rely on verified ground-station data from Italian meteorological authorities, with no model revisions or sensor discrepancies emerging in the final observation window. Only an unexpected late-day spike above 13°C or a post-event data correction could have altered the outcome.