Jeddah's coastal setting on the Red Sea produces typical August daily highs near 37–38°C under the influence of subtropical high pressure, intense solar insolation, and moderate humidity that limits extreme peaks compared with inland sites. Recent mid-August observations and short-range model guidance from agencies such as the Saudi National Center for Meteorology show daytime maxima consistently in the mid-to-upper 30s°C with minimal day-to-day variability, supporting the market's concentration on 36°C, 37°C, and 38°C outcomes. No major synoptic shifts, such as unusual Red Sea troughs or Saharan air intrusions, appear imminent for August 21, keeping probabilities aligned with long-term climatology while acknowledging that final observed values can shift with localized wind or cloud changes.