Current National Weather Service and private forecast models indicate Denver's overnight low on September 28 will likely fall in the low-to-mid 50s °F amid increasing cloud cover, a 40% chance of showers, and a modest frontal boundary. This setup favors the closely matched market-implied odds near 51 °F or below versus higher bins, as radiational cooling under partial clearing competes with warmer advection and urban heat island effects that often keep city lows several degrees above the 1991–2020 climatological average of 44 °F. Model consensus shows limited spread, but small shifts in timing of any showers or wind could tip the minimum across the 51 °F threshold. Updated NWS guidance expected within 24–48 hours will provide the next key data point for traders.