Recent Météo-France guidance and ECMWF/GFS ensemble forecasts project a Paris overnight low of 5-7°C on May 16 amid an unusual mid-May cool spell driven by persistent northerly airflow and overcast skies limiting daytime heating, explaining the tight clustering of market-implied probabilities around 4-7°C outcomes. Trader sentiment reflects model spread, with slight edge to 4°C from scenarios of partial clearing enabling radiative cooling, while urban heat island effects and variable winds could nudge toward 6-7°C; this is well below climatological norms of 9-10°C for mid-May. Key differentiators include cloud cover persistence and exact timing of any showers, with new model runs expected daily through resolution at Paris-Le Bourget Airport.