Current ensemble forecasts from the European Centre for Medium-Range Weather Forecasts center Paris overnight minimum temperatures on May 20 near 11–12 °C, producing the tight clustering of market-implied odds around those bins. A lingering Atlantic low-pressure pattern is sustaining variable cloud cover and light winds that limit radiative cooling, while scattered showers could further moderate the low. Model spread remains wide because small shifts in cloud timing or wind direction within the next 72 hours can swing the minimum by 2–3 °C. Traders are therefore pricing the full distribution of plausible outcomes rather than a single deterministic value, with the 9–13 °C range capturing nearly all probability mass.