The market's tight clustering around 20–21 °C for Qingdao’s May 18 maximum reflects broad agreement among global and regional forecast models on a typical mid-May coastal regime moderated by the Yellow Sea. Persistent marine air and the city’s shoreline location limit daytime heating, producing daily highs that historically average near 20 °C this week of the month. Minor differences among leading outcomes hinge on subtle variations in predicted wind direction, cloud cover, and the timing of any weak warm advection ahead of a possible frontal passage; a stronger sea breeze or thicker marine layer would cap readings near 20 °C, while clearer skies and lighter winds could briefly push the peak to 21–22 °C. Traders are watching the next China Meteorological Administration and ECMWF runs for refinements ahead of the 18 May resolution window.