The National Oceanic and Atmospheric Administration (NOAA) publishes the deciding data in its Climate at a Glance city time series, and the deciding value is the 1-month average temperature for Chicago, Illinois, as defined and displayed by NOAA, for September 2026, in degrees Fahrenheit. The outcome is Yes if that value exceeds the value specified in the market question and No otherwise. Only the initial value shown at the scheduled resolution time counts. The value becomes final when NOAA updates Climate at a Glance with that month's data, typically within the first two weeks of the following month, with resolution at 10:00 AM CT, and early resolution does not apply. If NOAA delays the update, resolution waits until the data is published.

The National Oceanic and Atmospheric Administration (NOAA) publishes the deciding data in its Climate at a Glance city time series, and the deciding value is the 1-month average temperature for Chicago, Illinois, as defined and displayed by NOAA, for September 2026, in degrees Fahrenheit. The outcome is Yes if that value exceeds the value specified in the market question and No otherwise. Only the initial value shown at the scheduled resolution time counts. The value becomes final when NOAA updates Climate at a Glance with that month's data, typically within the first two weeks of the following month, with resolution at 10:00 AM CT, and early resolution does not apply. If NOAA delays the update, resolution waits until the data is published.