Overview

• Stacker used National Centers for Environmental Information records to rank each state's hottest Septembers by average statewide temperature since 1895.
• Recent years lead many states: California's top month is September 2020 at 74°F, Texas is September 2023 at 81.8°F, and Arizona is September 2024 at 76.4°F.
• Oregon's record is a tie between 2011 and 2020 at 62.6°F, while Colorado's hottest September is 2019 at 62.9°F.
• The compilations were republished by local outlets this week as retrospective summaries rather than reports of new September 2025 records.
• The coverage situates the rankings within a documented warming trend of roughly 0.14°F per decade since 1880, echoed by NOAA's finding that July 2022 was the U.S. mainland's third hottest on record.