Abstract: Based on the daily and monthly meteorological observation data from 19 meteorological stations in Hainan, an analysis was made of the important climatic characteristics in Hainan, especially Hainan Island from the states of climate, extremes and disasters. The results show that the average annual temperature in Hainan is higher than 23 ℃, lower in the middle mountainous area and higher in the coastal area. The monthly variation of the temperature shows an almost symmetrical unimodal distribution, with the peak in June to July. The annual mean rainfall is over 900 mm, highly different between the east and the west of Hainan island, with the highest being above 2 000 mm in the east and the windward side of the southeast of Wuzhishan Mountain. The monthly rainfall shows a staircase asymmetrical unimodal distribution, with the peak in September. The annual sunshine hours are over 1 700 h, higher in the coastal area than in the northern inland and central mountainous areas, and their monthly variation has a bimodal distribution, with the primary peak in July and the secondary one in May, and the valley in February, showing a distinct feature of rain, heat and light in the same season. The extreme maximum temperature in Hainan Island is above 38 ℃, higher in the north than in the south, with the highest being upto 41.1 ℃ in the high value centers; the extreme minimum temperature in the central mountain area is lower than that in the surrounding areas, and is close to or lower than 0 ℃, with the lowest being −1.4 ℃. The maximum annual rainfall in each region is over 1500mm, and the minimum annual rainfall is below 1 500 mm; the longest stretch of consecutive days of rainfall is more than 26 days, and occurs mostly in August to September, and the longest stretch of continuous days of no rainfall is close to or more than 30 days; the maximum daily rainfall in each region is more than 300 mm, and the maximum rainfall is more than 600 mm. High temperature occurs mainly in May to July in Hainan Island, and the average days with high temperature are about 20 days, more in the north than in the south. The low temperature and rainy processes are common in the north of Wuzhishan mountain, where annual low temperature and rainy processes occur once or twice, about 10 days, but rare in the south of Wuzhishan mountain. The average annual rainstorm days of the whole island is about 8 days, and their monthly distribution is asymmetrically unimodal. The number of rainstorm days increases slowly from May to October, and decrease dramatically from October to November. Rainstorm which happens over half of the island is very low in probability, and that over the whole island is very rare, but all occurred after 2 000. Drought is common in the island, and it occurs frequently in winter and spring in the west and the south coast of the island. Continuous drought in other areas of the island is also observed in winter and spring when there is low typhoon rainfall in the autumn.