Stable high-pressure conditions over western Europe are anchoring trader focus on overnight radiative cooling under mostly clear to partly cloudy skies and light northeast winds for Paris on September 24. Official and ensemble guidance from sources including Météo-France-aligned models and global outputs cluster the expected minimum between 12–14 °C, with 13 °C and 12 °C outcomes capturing the tightest market-implied odds because subtle differences in cloud timing and boundary-layer mixing can shift the low by 1 °C. Dew points near 10–12 °C and modest wind speeds favor efficient heat loss after sunset, while the seasonal baseline low of roughly 11 °C provides context for why warmer recent anomalies have not fully displaced cooler probabilities. Resolution hinges on the official Paris-Montsouris reading at the coldest hour before dawn.