Trader consensus on Polymarket closely clusters around 27°C (28%) and 28°C (24.5%) for Shenzhen's highest temperature on May 17, reflecting China Meteorological Administration forecasts showing persistent moderate to heavy rain through the weekend, capping peaks after May 13's 31°C outlier under clearer skies. Ongoing convective showers and thick cloud cover from a southward monsoon trough limit solar insolation, with high humidity near 80% and sea breezes off the South China Sea further moderating daytime heating in this subtropical coastal city. Model ensembles indicate slight uncertainty in cloud breaks—potentially allowing urban heat island effects to push toward 28°C—while 26°C trails at 18.5%. Updated guidance expected May 16 could shift odds as observations refine intensity forecasts.