Recent short-range forecast model runs for Helsinki show notable divergence in overnight low temperatures on September 1, with ensemble guidance split between scenarios supporting a minimum near or below 8°C under clearer, calmer conditions and warmer outcomes near or above 18°C if cloud cover or stronger winds limit radiative cooling. Historical data place the typical September 1 low at approximately 11–12°C, but late-August atmospheric patterns featuring variable Atlantic flow and frontal activity introduce uncertainty in boundary-layer stability and moisture. This genuine spread in guidance, rather than a single dominant signal, underpins the near-even market-implied probabilities for cooler versus milder extremes while compressing odds on intermediate values around the climatological mean. Updated runs from the Finnish Meteorological Institute and ECMWF over the next 24–48 hours will likely resolve much of the spread ahead of market resolution.