NWS forecasts and model consensus for Miami on October 4 point to a high near 89°F under mostly sunny skies with southeast winds of 10-15 mph, driving the near-even market split between the 88-89°F and 90-91°F bins. Warm, humid air masses typical of early October in South Florida, with dew points in the upper 70s, sustain elevated heat indices above 100°F while limited cloud cover and weak steering patterns allow strong diurnal heating. Minor model differences in afternoon wind shifts or sea-breeze timing create the narrow uncertainty between those two ranges, as stronger mixing or brief cloud increases could cap the peak just below 90°F. Updated NWS briefings and next model runs will clarify resolution thresholds.