Recent National Weather Service forecasts for Chicago O'Hare project a Sunday high near 71°F under increasing afternoon clouds, with southwest winds shifting northwest at 5–10 mph. This central guidance anchors trader sentiment around the 70–75°F range, where the 72–73°F and 74–75°F bins together exceed 70% implied probability. Model spreads arise from subtle differences in boundary-layer mixing and cloud timing, which can shift peak readings by 2–3°F. Climatological context shows an October 4 average high of 68.5°F, so current guidance reflects mild warmth from southerly flow ahead of the frontal passage. Updated model runs and NWS briefings through early Sunday will refine these temperature thresholds before market resolution.