Wellington’s late-winter maritime climate keeps daily maxima tightly clustered near the 12–14 °C climatological average, with current forecasts from MetService and international models pointing to a peak of 13–15 °C on 10 August amid a slow-moving front and associated rain. Northerly flow ahead of the system favors modest warming, while increasing cloud cover and precipitation limit solar heating and cap the high, producing the tight 42.5 % / 38.5 % split between the 14 °C and 13 °C outcomes. Model runs show limited spread once the front arrives, so small shifts in timing or wind direction could decide the exact maximum recorded at the official Kelburn site. Traders are weighting the most recent guidance that places the likely range at the upper end of normal August values without exceeding 15 °C.