Forecast uncertainty for Milan on August 17 centers on the balance between persistent high pressure supporting daytime heating near 32–33°C and the risk of increasing convective instability that could trigger thundery showers, capping the maximum through cloud cover and evaporative cooling. Official guidance from agencies like the Italian meteorological service and European models shows modest disagreement on timing and coverage of instability, with some runs indicating isolated storms capable of limiting the peak by 1–2°C while others keep conditions clearer for higher readings. These near-term variables—boundary-layer moisture, wind shear, and surface energy fluxes—explain why market-implied probabilities cluster tightly around 31–33°C rather than extremes, reflecting traders’ assessment of the narrow window between typical late-summer Po Valley warmth and potential afternoon convection. Updated model runs and radar trends tomorrow morning will likely refine resolution criteria for the daily high.