Trader consensus on Polymarket favors 18°C at 38.5% implied probability for Paris's highest temperature today, narrowly ahead of 19°C at 30%, reflecting close alignment in latest Météo-France and ensemble forecasts from ECMWF and GFS models under a dominant anticyclone ridge bringing mostly sunny skies and light winds. This positioning stems from recent model runs showing peak afternoon heating around 18-19°C amid mild spring conditions slightly above the April climatological average of 16°C, with differentiating factors including variable low-level cloud intrusions from the west and urban heat island amplification in late afternoon. Uncertainty persists due to ensemble spreads of 1-2°C; real-time observations from the official Paris-Montsouris station will resolve the market by midnight.