Official forecasts from MetService and supporting models project a maximum of 9–10°C in Wellington on August 16 under strong southerly winds and occasional showers, consistent with a recent polar air outbreak that has kept daily highs near or below the August climatological average of roughly 13°C. This cold advection, combined with limited solar heating in mid-winter and the typical “Wellington breeze effect,” underpins the market’s overwhelming 93.5% implied probability for 10°C. Ensemble guidance shows tight clustering around this range, with only modest uncertainty from exact timing of any clearing or minor wind shifts. A rapid northerly flow change or unexpected subsidence could allow brief warming toward 12°C, though current observations and model consensus make such a jump unlikely before resolution.