The appropriate season on islands in Zhejiang is studied by means of the body-sensible index,wind index and comfortability index,respectively;and the concept of "comfortable frequency" is presented.The necessary revision is conducted on the comfortability index according to the features of island tourism.The results show that the revised comfortability index,which combines seven meteorological factors(air pressure,sunshine,precipitation,temperature,humidity,wind and visibility),can evaluate synthetically the reaction of human bodies to weather.It can be used to appraise more completely the economic development value of a scenic spot and the length of the appropriate season for tourism.The longer the appropriate season is,the higher the development value of the scenic spot is.