Md. Abdullah Al Mamun ¹ Sheikh Arafat Islam Nihad ² Md Abdur Rouf Sarkar ^3,4* Mou Rani Sarker ⁵ Md. Arafat Hossain ⁶ Oliver Obročník ⁷ Viliam Bárek ⁷ Marian Brestic ⁸ Akbar Hossain ^9*

• ¹ Agricultural Statistics Division, Bangladesh Rice Research Institute, Gazipur, Bangladesh
• ² Plant Pathology Division, Bangladesh Rice Research Institute, Gazipur, Bangladesh
• ³ Agricultural Economics Division, Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh
• ⁴ School of Economics, Zhongnan University of Economics and Law, Wuhan, Hebei Province, China
• ⁵ Sustainable Impact Platform, International Rice Research Institute, Dhaka, Bangladesh
• ⁶ Biotechnology Division, Bangladesh Rice Research Institute, Gazipur, Bangladesh
• ⁷ Department of Water Resources and Environmental Engineering, Faculty of Horticulture and Landscape Engineering, Slovak University of Agriculture, Nitra, Slovakia
• ⁸ Institute of Plant and Environmental Sciences, Slovak University of Agriculture, Nitra, Slovakia
• ⁹ Department of Soil Science, Bangladesh Wheat and Maize Research Institute (BWMRI), Dinajpur, Bangladesh

Bangladesh, being one of the most agriculturally reliant and climate-vulnerable countries, requires real-time quantification of climatic variables such as temperature to identify potential threats to sustainable food security. This study addresses the knowledge gap concerning spatial and temporal temperature variations and their impact on rice yield in Bangladesh, particularly focusing on Aus, Aman, and Boro seasons. Temperature data from 35 meteorological stations in Bangladesh from 1970 to 2020 were analyzed using parametric and nonparametric tests, including the Mann-Kendall test, K-means clustering, wavelet coherence analysis, and regression. The results found that the average minimum temperature was 21.34°C, and the average maximum temperature was 30.57°C. The highest mean temperature was recorded in May at 37.1°C, while the lowest was observed in January at 8.4°C. The minimum temperature fluctuation is more visible and increases at a faster rate than the maximum temperature. Most of the studied stations showed a significant increase in maximum, minimum, and mean temperatures during the monsoon season. An increase in minimum temperature had a significant incremental impact on Aus rice yield in seven regions. Furthermore, the results indicated that an increase in the frequency of days experiencing temperatures exceeding 35°C has been demonstrated to reduce rice yield, particularly in the significantly affected northwestern region. The heat incidence validates those temperatures during the Aus season surpassed than Aman and Boro seasons. Recent years witnessed a notable impact of heat incidents on both Aus and Boro season rice yields, with frequencies exceeding 9 adversely affecting Aus and Aman season rice yields. Regression analysis showed that temperature parameters explained rice yield variations ranging from 11-47% for Aus, 4-70% for Aman, and 7-52% for the Boro season in different parts of Bangladesh. Despite the adverse effects of increasing temperature, Bangladesh has achieved rice self-sufficiency through the widespread adoption of stress-tolerant rice varieties, modern farm machinery, irrigation, fertilizers, and pesticides, which significantly contribute to rice production in the country. Therefore, except for a few extreme events, Bangladesh did not experience significant impacts on rice production due to temperature events. These results hold practical significance for regional policy planning to achieve food security in Bangladesh.