string str="2008-07-20多云26℃～33℃微风2008-07-21阵雨转多云26℃～34℃微风2008-07-22雷阵雨转多云26℃～34℃微风";
System.Text.RegularExpressions.Regex  reg=new  System.Text.RegularExpressions.Regex("(?<Date>[0-9-]{1,})(?<Weather>[\u4e00-\u9fa5]{1,})(?<Temperature>[0-9-℃～]{1,})(?<Wind>[\u4e00-\u9fa5]{1,})",System.Text.RegularExpressions.RegexOptions.IgnoreCase);  
System.Text.RegularExpressions.MatchCollection m = reg.Matches(str); //设定要查找的字符串
string newstr="当前天气："+ m[0].Groups["Weather"].ToString() + m[0].Groups["Temperature"].ToString()+m[0].Groups["Wind"].ToString()+" 明日天气："+ m[1].Groups["Weather"].ToString() + m[1].Groups["Temperature"].ToString()+m[1].Groups["Wind"].ToString()+" 后日天气："+ m[2].Groups["Weather"].ToString() + m[2].Groups["Temperature"].ToString()+m[2].Groups["Wind"].ToString();
Response.Write(newstr);