Trader consensus on Polymarket closely splits between 90-91°F (30.5%) and 88-89°F (29.0%) for Austin's highest temperature on April 17, driven by the latest National Weather Service guidance and ensemble forecasts from GFS and ECMWF models indicating peaks in the upper 80s to low 90s amid a building upper-level ridge over Texas. This follows early April's unsettled pattern of storms and rain, which has given way to drier conditions and southwesterly winds advecting warmer air, boosting diurnal heating above the mid-April climatological normal of 80°F. Differentiating factors include uncertainty in afternoon cumulus cloud development from lingering low-level moisture, potentially capping highs by 1-2°F, plus Austin's urban heat island effect amplifying late-day temperatures. Watch for the NWS Austin/San Antonio office's afternoon forecast discussion for refined model runs.