Recent ensemble forecasts from European meteorological centers point to a minimum temperature in Paris on May 18 near 9 °C, driven by a weakening cold-air intrusion and increasing cloud cover that limits nocturnal radiative cooling. Mid-May climatology shows an average overnight low of 9–10 °C, and current model consensus aligns closely with this baseline after several days of subnormal readings earlier in the month. Differences among the leading outcomes hinge on small variations in forecast wind speeds and boundary-layer moisture: lighter winds or clearer skies could allow the mercury to dip to 8 °C, while modest advection of milder Atlantic air or thicker low clouds would hold the low at 10 °C. Traders are therefore pricing the narrow 8–10 °C band most heavily, reflecting the narrow uncertainty range typical of short-range temperature prediction three days ahead.