Traders' near-unanimous consensus on a 25°C high in Shenzhen on March 21 stems from authoritative forecasts from the China Meteorological Administration and global models like ECMWF, which converge on a daytime maximum of 24-26°C amid mild southerly flows and seasonal norms. Historical data shows March 21 averages around 23°C, with rare exceedances above 27°C, reinforcing this positioning as low-volatility spring weather prevails under neutral ENSO conditions. Challenges could arise from an unforeseen subtropical ridge strengthening, pushing convective heating higher, or urban heat island amplification in Shenzhen's dense core, though ensemble probabilities assign under 5% odds to deviations beyond 26°C.