Trader consensus on Polymarket reflects tight clustering around 21–23°C for Busan's highest temperature on April 19, driven by Korea Meteorological Administration (KMA) short-range forecasts and global model ensembles like GFS and ECMWF projecting peaks in this range under persistent high-pressure ridging and southerly winds. Recent mild conditions—clear skies yielding highs of 19–22°C over the past week, exceeding the mid-April climatological average of 18°C—have boosted these implied probabilities, with April 14 and 17 observations confirming above-normal warmth. Differentiating factors include model spread on afternoon sea breeze timing, potential low-level clouds, and coastal cooling effects, introducing uncertainty in peak heating. KMA updates twice daily and overnight ensemble refreshes could refine guidance ahead of resolution based on official station measurements.