Trader consensus on Polymarket reflects tight uncertainty in National Weather Service forecasts for Chicago O'Hare's high temperature today, with implied odds favoring 74°F or higher at 43.5% over 72-73°F at 35%, driven by a persistent warm ridge aloft ushering 850 mb temperatures near 15-18°C into the Midwest. Recent 00Z GFS and ECMWF runs project peaks near 78-82°F under partly sunny skies, but NWS guidance tempers expectations to the mid-70s due to a 30-50% chance of scattered afternoon showers and thunderstorms from a passing shortwave trough, potentially increasing cloud cover and capping daytime heating. Yesterday's 82°F record underscores the setup's potential, though convective timing and coverage remain key differentiators—earlier storms favor lower outcomes, while delayed activity allows upper-70s peaks. Monitor hourly observations through late afternoon for resolution.