**Forecast models show the lowest temperature in Wellington on September 5, 2026, most likely falling in the 11–13°C range, with the market’s tight clustering around 12°C (37.5%) and 13°C (30.5%) reflecting this narrow consensus amid notable spread in lower-probability outcomes.** Northwesterly flow dominates the immediate outlook, advecting relatively mild maritime air and limiting overnight radiative cooling under partly cloudy skies. Official guidance, including Met Office and multiple regional models, centers the overnight minimum near 12°C, consistent with early-spring norms slightly elevated by the strong ongoing El Niño, which favors warmer baselines and greater temperature variability across New Zealand. However, model divergence on cloud cover, wind strength, and any late southerly shift creates realistic pathways for either a milder 13°C floor or a sharper drop toward 9–11°C (or lower) if clearer conditions allow more efficient heat loss. The elevated 28% probability on 7°C or below captures tail-risk scenarios from stronger cooling or timing shifts, while warmer tails (17°C+) remain negligible given the seasonal context. Traders are weighting the latest high-resolution runs and MetService updates, which will refine the minimum ahead of the overnight period.