Resolution criteria

This market will resolve to YES if September 2026 is declared the warmest September on record globally by the Copernicus Climate Change Service. The market resolves to YES if either of the following conditions are met:

1. The Copernicus monthly climate bulletin for September 2026 states that September 2026 was the warmest September on record globally

2. The global average surface air temperature for September 2026 in the ERA5 dataset exceeds 16.38°C, the record set in September 2023

In the event of a tie, this market will resolve NO. September 2026 must exceed the 2023 record for this market to resolve YES

Sources:

• Primary source: Copernicus Climate Bulletins

• Fallback source: If Copernicus data is unavailable, the market will resolve using the NOAA NCEI Global Climate Report for September 2026. It will resolve to YES if the global temperature anomaly for September 2026 exceeds the September 2023 record of 1.44°C (2.59°F) above the 20th-century average.

The current record for the hottest September globally was set in September 2023, which registered an average global surface air temperature of 16.38°C (0.93°C above the 1991–2020 baseline according to Copernicus, and 1.44°C above the 20th-century average according to NOAA).