A bar chart showing the monthly global air surface temperature anomalies from 1940–2023 for September, compared to the 1991–2020 baseline. From 1940 to 2010 the deviations were primarily negative, ranging from -0.9°C to 0.1°C. From 2010 to 2023 all deviations were positive, and show an increasing trend, with the largest deviation at +0.93°C in 2023.