**Persistent thunderstorm activity and high humidity are the main drivers keeping Miami's overnight low on October 1 in the mid-to-upper 70s.** Short-term forecasts from the National Weather Service and WeatherBug indicate a low near 76–78 °F under mostly cloudy skies with showers and thunderstorms likely, consistent with the market’s leading bins at 76–77 °F (37 %) and 78–79 °F (35.5 %). In Miami’s subtropical climate, the daily minimum temperature is shaped by radiational cooling after sunset, modulated by cloud cover, dew point, and wind. Thunderstorms and thick cloud decks limit outgoing longwave radiation, often holding lows 2–4 °F above clear-sky values. Persistent easterly flow off the warm Atlantic also supplies high moisture (dew points near 75 °F), reducing the diurnal temperature range. Historical early-October climatology shows average lows of ~74–76 °F, so the current pattern sits slightly above normal but within typical variability. Model consensus through the next 48 hours shows no strong cold front or dry-air intrusion that would allow deeper cooling. Minor differences in storm timing or coverage could shift the exact low by 1–2 °F, which is why the two central bins remain closely matched. Later updates from the National Hurricane Center or local NWS offices on steering patterns and rainfall timing will provide the clearest signals for any last-minute adjustments in trader positioning.