Official National Weather Service observations at Austin Bergstrom International Airport recorded a daily maximum of 100°F on September 5, 2026, aligning precisely with the market's dominant 100-101°F outcome at near-certainty. This reflects typical early-September conditions in central Texas, where persistent high pressure and southerly flow often sustain highs near or above 95°F, exceeding the 1991-2020 average of 93.6°F for the date. Late-summer heat indices near 105°F further supported trader confidence in this narrow range. Final verified data or minor station-to-station variations could theoretically shift the exact peak, though multiple reports converged on 100°F with no precipitation to alter readings.