**Current medium-range forecasts for Helsinki on August 28, 2026, indicate overnight lows clustered around 13–15 °C, aligning closely with the tightly bunched market-implied odds near those levels.** Models such as those referenced by FMI, ECMWF, and GFS runs available as of August 26 show a mild airmass with daytime highs near 19–20 °C and nighttime radiative cooling limited by light southeasterly winds (4–8 mph) and partly cloudy skies, keeping minimum temperatures from dropping much below the seasonal norm. The primary scientific drivers differentiating the 13 °C, 14 °C, and 15 °C outcomes include variations in cloud cover and boundary-layer mixing: clearer skies would enhance longwave radiative loss and favor the lower end (near or slightly above the 12.1 °C 1991–2020 average low), while increased low-level moisture or wind would suppress cooling toward 15 °C. Dew-point temperatures in the mid-50s °F (around 13–14 °C) further constrain how far the air can cool before saturation effects moderate the drop. Historical analogs from recent years show similar late-August nights ranging 8–15 °C under comparable high-pressure influence, underscoring the narrow uncertainty band. Traders are weighting the consensus of multiple model cycles showing stable conditions without significant cold-air advection or frontal passages before resolution. Key upcoming catalysts include updated FMI probability forecasts and higher-resolution runs over the next 48 hours, which could shift the distribution if cloud or wind fields evolve. Lower-probability tails (below 10 °C or 16 °C+) reflect the low likelihood of atypical extremes given the current synoptic pattern.