A strong heatwave driven by a high-pressure dome and northward advection of subtropical air has elevated minimum temperatures across Paris ahead of June 19. Official guidance and ensemble models from Météo-France and European centers indicate overnight lows stabilizing near 22–23 °C under persistent clear skies and light winds that limit radiative cooling. This setup deviates from June climatological norms of 12–15 °C, pushing market-implied probabilities toward those warmer thresholds. Updated model runs show limited cooling potential before dawn, with only modest variability expected from localized urban heat-island effects. Traders are therefore concentrating positions around the 21–23 °C range as the most consistent forecast outcome.