**Trader consensus on 17°C as the highest temperature in Paris on October 8 reflects real-time meteorological observations confirming a daily maximum of 17°C.** Multiple forecast models and station reports showed temperatures rising from morning lows near 11–13°C under clearing skies and northwest winds to an afternoon peak of 17°C before declining, consistent with the climatological average high of roughly 17.8°C for the date. With the observation window now closed and no model runs or station revisions indicating a higher value, implied probability for this outcome reached 100%. Minor uncertainty remains only if official post-day quality-controlled data from primary stations differ slightly from preliminary readings.