{
 "error": 0,
 "status": "success",
 "date": "2014-03-04",
 "results": [{
  "currentCity": "成都",
  "weather_data": [{
   "date": "周二(今天, 实时：12℃)",
   "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/duoyun.png",
   "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/duoyun.png",
   "weather": "多云",
   "wind": "北风微风",
   "temperature": "15 ~ 6℃"
  }, {
   "date": "周三",
   "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/yin.png",
   "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/xiaoyu.png",
   "weather": "阴转小雨",
   "wind": "北风微风",
   "temperature": "14 ~ 7℃"
  }, {
   "date": "周四",
   "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/xiaoyu.png",
   "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/xiaoyu.png",
   "weather": "小雨",
   "wind": "北风微风",
   "temperature": "12 ~ 7℃"
  }, {
   "date": "周五",
   "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/xiaoyu.png",
   "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/xiaoyu.png",
   "weather": "小雨",
   "wind": "南风微风",
   "temperature": "9 ~ 6℃"
  }]
 }]
}

uses
  REST.Json,
  System.Json,
  System.Types,
  System.Json.Types,
  System.Json.Writers,
  System.Json.Builders,
  System.Json.Serializers;

procedure TForm1.Button7Click(Sender: TObject);
var
  m_JSONObject: TJSONObject;
  m_Item1, m_Item2, m_Item3, m_Item4: TJSONValue;
  m_Weather: TJSONArray;
  m_Str: string;
  m_Result: string;
  I: Integer;
begin
  // 读JSON文本
  m_Str := Trim(Memo1.text);
  // 防止乱码
  m_JSONObject := TJSONObject.ParseJSONValue(TEncoding.UTF8.GetBytes(m_Str), 0) as TJSONObject;
  // 读取results的数据
  m_JSONObject := (m_JSONObject.GetValue('results') as TJSONArray).Get(0) as TJSONObject;
  // 读取results中的weather_data的数组
  m_Weather := m_JSONObject.GetValue('weather_data') as TJSONArray;
  // 循环读天气数据
  for I := 0 to m_Weather.size - 1 do
  begin
    // 取天气值
    m_Item1 := (m_Weather.Get(I) as TJSONObject).GetValue('date');
    m_Item2 := (m_Weather.Get(I) as TJSONObject).GetValue('weather');
    m_Item3 := (m_Weather.Get(I) as TJSONObject).GetValue('wind');
    m_Item4 := (m_Weather.Get(I) as TJSONObject).GetValue('temperature');
    // 输出
    Memo2.Lines.Add(Format('【日期%s】,【天气%s】,【风速%s】,【温度%s】', [m_Item1.Value, m_Item2.Value, m_Item3.Value, m_Item4.Value]));
  end;
  m_JSONObject.Free;
end;