According to the documentation of scatter charts:
Unlike the line chart where data can be supplied in two different formats, the scatter chart only accepts data in a point format.
So you can't use values like 2017-07-08T06:15:02-0600 . You can convert dates into numbers and use them in your data.
In your case:

data: [{
        x: 1499516102000,
        y: 23.375
    }, {
        x: 1499516402000,
        y: 23.312
    }, {
        x: 1499516702000,
        y: 23.312
    }, {
        x: 1499517002000,
        y: 23.25
    }
]

Now your xAxes will be with numbers, so you can use a callback to modify xAxes labels.

这个建议并不完全正确。javascript moment.js允许使用日期作为x轴值来绘制散点数据。由于某种原因，Chart.bundle.js中的捆绑版本对我不起作用，所以我直接下载了moment.js。我用它来设置：

<script src="js/moment.js"></script>
<script src="js/Chart.min.js"></script>

下面是chart.js数据的详细信息：

data: [
  {x: moment("2017-07-08T06:15:02-0600"), y: 23.375},
  {x: moment("2017-07-08T06:20:02-0600"),y: 23.312},
  {x: moment("2017-07-08T06:25:02-0600"),y: 23.312},
  {x: moment("2017-07-08T06:30:02-0600"),y: 23.25}
],

效果很好！

Another solution that worked great for me, was to just use the line type for the chart, configure it for using dates for the x axis, and addtionally disable the lines, so that it just looks like a scatterplot.

new Chart(ctx, {
        type: 'line',
        data: {
            datasets: [{
                x: 2017-07-08T06:15:02-0600,
                y: 23.375
              },{
                x: 2017-07-08T06:20:02-0600,
                y: 23.312
              },{
                x: 2017-07-08T06:25:02-0600,
                y: 23.312
              },{
                x: 2017-07-08T06:30:02-0600,
                y: 23.25
            }]
          },
          options: {
            showLine: false,
            scales: {
              x:{
                type: 'time',
                display: true,
                title: {
                  display: true,
                  text: 'Date'
                },
              },
            }
          }
       }
    );

I see this as a quite elegant solution. The documentation even specifies:
The scatter chart supports all of the same properties as the line chart. By default, the scatter chart will override the showLine property of the line chart to false.