**Approaching frontal system and associated cloud cover, showers, and northerly flow are the main drivers splitting trader sentiment on Denver’s September 30 minimum temperature.** Official National Weather Service guidance and several model runs point to a low near 50°F amid mostly cloudy skies, a 40-50% chance of showers, and light-to-moderate northerly winds, consistent with the narrow 48–51°F bins carrying meaningful probability. However, the near-even odds on ≤47°F versus ≥66°F reflect genuine short-range forecast divergence: stronger or earlier northerly advection and clearer breaks could allow greater nocturnal radiative cooling toward the mid-40s, while persistent cloud cover, higher dew points, or delayed cooling would keep readings in the upper 50s or low 60s. Historical climatology (average low ~43°F) provides context but is overridden by the active weather pattern two days out. Updated model runs and NWS briefings through September 29–30 will likely resolve the key variables of cloud timing and boundary-layer mixing.