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Attempts are made to study the seasonal climatology of the Arabian Peninsula, including the regional to station level information for Saudi Arabia for the period 1979-2009. The wet (November to April) and dry (June to September) season rainfall and temperature climatology are obtained from various data sources, namely, surface observations, CPC Merged Analysis of Precipitation (CMAP), Climatic Research Unit (CRU) and Tropical Rainfall Measuring Mission (TRMM). These gridded datasets detect the dry zone over the Rub Al-Khali, the world’s largest sand desert, during the wet season. In this season, large rain belts exist north of 30 degrees N and south of 15 degrees N. During the dry season, the Arabian Peninsula is almost entirely dry north of 15 degrees N but rain belts exist below this latitudinal boundary. Irrespective of the season or dataset used, a relatively heavy-rain area is obtained for the southwest of the Peninsula. The wet (dry) season temperature is highest over the western (middle to the northern) parts of the Peninsula. Surface observations indicate that, irrespective of season, rainfall insignificantly increased in the first period (1979-1993), and then significantly decreased in the second period (1994-2009). The decrease rate is 35.1 mm (5.5 mm) per decade during the wet (dry) season. The temperature over Saudi Arabia has increased significantly, and the increase rate is faster (0.72 degrees C per decade) in the dry season compared to the wet season (0.51 degrees C per decade). (C) 2012 Elsevier B.V. All rights reserved.