Wellington’s August 11 high has locked at the 12°C outcome in trader consensus because official forecasts from MetService and NIWA show a cool southerly flow under mostly cloudy skies, keeping maximum temperatures aligned with the city’s long-term August climatological mean of roughly 12°C. Real-time surface observations and model runs confirm limited insolation and no significant warm-air advection, producing a tight temperature distribution unlikely to deviate from this value. The only realistic challenges would be an unforeseen clearing trend that boosts daytime heating or a rapid wind shift introducing milder northerly air, both of which current guidance assigns negligible probability before the daily maximum is recorded.