Strong southerly winds advecting cooler polar maritime air, combined with persistent low cloud cover, are suppressing daytime heating in Wellington and anchoring forecasts for an August 16 maximum near 9–10 °C, well below the seasonal average of roughly 12–13 °C. Official guidance from MetService and NIWA highlights this pattern through the weekend, with minimal model disagreement on temperatures remaining capped by the maritime airstream and limited insolation. Traders have therefore assigned overwhelming implied probability (96 %) to a 10 °C peak, reflecting the tight clustering of deterministic and ensemble guidance around that threshold. A rapid wind shift to northerly flow or unexpected clearing that boosts solar radiation could still push readings to 11 °C, though current observations and short-range model runs indicate low likelihood of such changes before resolution.