**Trader consensus clusters tightly around 7–9°C for Helsinki’s lowest temperature on October 15, 2026, reflecting model agreement on mild overnight conditions.** Southerly flow and persistent cloud cover have limited radiative cooling, keeping surface temperatures elevated relative to the October climatological mean of roughly 7°C. Hourly guidance from multiple sources shows early-morning readings bottoming near 8–10°C under overcast skies with light winds, while slight model spread in boundary-layer mixing and exact timing of any partial clearing creates the narrow probability band. Official monitoring (Finnish Meteorological Institute equivalents) and ensemble spreads emphasize that small variations in cloud thickness or local urban heat effects could shift the precise minimum by 1°C, sustaining the close contest among the leading outcomes.