Vol. 129, No. 4 * Pages 373–484 * October - December 2025

This study analyzes long-term (1940–2023) monthly temperature trends across the Northern Hemisphere, focusing on tropical, temperate, and polar regions, as well as key mountainous areas such as the Rocky Mountains, the Tibetan Plateau, and the Alps. Results show that polar regions experienced the highest seasonal temperature increase, averaging 0.081°C per season during winter, while tropical regions exhibited the lowest increase, with 0.036°C during winter. In temperate regions, seasonal warming trends ranged from 0.05°C in winter to 0.039°C in summer. Monthly trends revealed that February and March exhibited the highest increases, with rates of 0.0195 °C and 0.0194 °C, respectively, while August showed the lowest increase at 0.0116 °C. Furthermore, trend maps indicate that over 92% of the Northern Hemisphere experienced warming across all months except June and January. These findings provide a comprehensive understanding of regional and seasonal temperature variations in the Northern Hemisphere, emphasizing the importance of localized and temporal analyses for a more nuanced perspective on climate change.