This chapter examines the historical trends of climate change over the Arabian Peninsula, emphasizing significant transformations in temperature and precipitation patterns over the past two to three decades. The analysis is based on a comprehensive review of literature, incorporating observational datasets such as Climate Research Unit (CRU), CPC Merged Analysis of Precipitation (CMAP) and Tropical Rainfall Measuring Mission (TRMM), along with statistical techniques including the Mann–Kendall test, Sen’s slope estimator and the seasonal-Kendall metric. Observational data indicates a pronounced warming trend across the region, with notable spatial variability. Studies based on both station data and global gridded datasets confirm a significant rise in annual mean temperatures, with warming trends being more spatially coherent and statistically significant than those observed for maximum temperatures. The most substantial warming has been recorded over the eastern and southeastern areas of the peninsula, particularly in countries like Oman and the United Arab Emirates (UAE). Site-specific station records further reveal that mean temperature increases in some locations are occurring at rates 1.5 to 3.5 °C times higher than the global average. Seasonal analyses highlight variations in warming trends, with significant increases in both maximum and minimum temperatures during certain periods. In contrast to temperature trends, precipitation patterns across the Arabian Peninsula exhibit lower spatial coherence. While most of the Arab world does not show clear increasing or decreasing trends in precipitation, specific regions such as northern Oman and Qatar have experienced notable drying trends during certain seasons. The influence of global climatic phenomena, including the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO), further contributes to climate variability in the region, reinforcing its vulnerability to global climatic teleconnections. While regional climate models and Intergovernmental Panel on Climate Change (IPCC) projections have often been scrutinized for potential exaggeration, observational data suggest that, in some cases, they may have even underestimated the extent of warming in the Arabian Peninsula. This underscores the importance of localized climate assessments and adaptive planning to inform sustainable development and enhance long-term resilience in the region.