请以json格式回答这个问题：请告诉我明天北京是什么天气？
user
```json
{
  "location": "北京",
  "date": "明天",
  "weather": {
    "condition": "晴",
    "temperature": {
      "high": 25,
      "low": 15
    },
    "wind": {
      "direction": "东北",
      "speed": "10 km/h"
    },
    "humidity": "40%"
  }
}
```
assistant