Persistent inter-monsoon convective activity across Singapore, with widespread thundery showers expected through May 17, continues to limit daytime heating despite official Meteorological Service Singapore forecasts calling for a potential peak near 33–34 °C under light northwest winds. Recent observations show maxima suppressed to 29–30 °C on consecutive days amid high humidity and cloud cover, aligning with May’s climatological average of 32.3 °C while deviating below the 35 °C readings seen in late April. This pattern of localized thunderstorms introduces uncertainty in afternoon model runs, supporting the market’s heaviest weighting on 33 °C or higher at 50.5 % implied probability alongside substantial shares for exactly 32 °C and 31 °C. Traders appear to discount the upper forecast envelope given ongoing convective suppression, with resolution dependent on the official Changi station daily maximum.