Abstract: Based on the observed meteorological data from 1953 to 2003,the main climate indices and the required climate conditions for umbilical orange growth and development were compared in the mountain areas of South Anhui Province and Zigui of Hubei Province.The water and thermal conditions and their changes in recent years in the mountain areas of South Anhui Province were analyzed.The climate suitability for umbilical orange planting in mountain areas of South Anhui Province was assessed.The result indicated that precipitation and sunlight conditions in the two areas were similar,while the thermal conditions in the mountain areas of South Anhui Province was worse than in Zigui of Hubei Province.The insufficient accumulated temperature of ≥10℃ influenced the fruit quality of umbilical orange.The main restricted factor for umbilical orange planting was too low extreme lowest temperature in winter in mountain areas of South Anhui.Thermal conditions still did not meet the needs for a safe overwintering of umbilical orange,although thermal conditions had been improved due to climate change.Therefore,the umbilical orange could only be planted in the warm sloping fields.The frozen disaster in the winter and drought in the summer and autumn was still needed to prevent.

Key words: Umbilical orange, Umbilical orange, Climate suitability, Climate change, Mountain areas of South Anhui Province