Current short-range numerical weather prediction models from MetService New Zealand cluster on an afternoon maximum of 13–15°C for Wellington on May 18 under a stable southerly regime and light winds across Cook Strait. This range aligns with mid-autumn climatology, where daily highs typically fall between 12°C and 15°C, and recent model runs show minimal day-to-day variability following a period of settled conditions. The 14°C outcome leads at 55.5% implied probability because most ensemble members keep peak temperatures from reaching the warmer threshold needed for 15°C while avoiding the cooler bias that would favor 13°C. Traders are watching the next MetService update and official observations from Wellington International Airport, as even a modest shift in wind direction or cloud cover could adjust the final reading by 1°C.