**High-pressure systems building over western Europe have stabilized clear to mostly clear skies for Paris on June 17, 2026, supporting efficient nocturnal radiative cooling after daytime highs near 30–33 °C.** Ensemble forecasts from Météo-France and international models cluster overnight lows in the 16–18 °C range, with trader-implied probabilities tightly bunched around 15–17 °C because small differences in boundary-layer wind, low-level humidity, or residual cloud cover can shift the minimum by 1–2 °C. Clear skies promote stronger surface heat loss after sunset, while light southwesterly winds (around 5–10 km/h) limit mixing and allow the urban heat island to moderate the coolest readings near the city center. Recent model runs show modest spread in the timing of any subtle moisture return, keeping the distribution centered near 16 °C yet leaving room for 15 °C or 17 °C outcomes depending on the final forecast update. Historical June climatology places typical Paris minima around 13–15 °C, but the current synoptic pattern favors values several degrees above average.