Forecast models for Wellington on August 29 show a tight cluster of possible overnight minima driven by variable northwesterly flow, limited cold-air advection from the south, and clearing skies that permit moderate radiative cooling. Ensemble guidance from sources such as the Met Office, GFS, and ECMWF places the lowest temperature between roughly 8–12 °C, with small differences in wind speed, cloud timing, and boundary-layer mixing explaining the even spread of market probabilities across those bins. Historical August minima average near 8–9 °C, so the current pattern sits close to climatology but lacks a strong southerly surge or high-pressure ridge that would push readings decisively lower or higher. Traders are therefore weighting near-term model updates on nocturnal cooling rates and any late-day frontal passage that could alter the final minimum.