How do I change the color for ng2-charts?

You should do this like:

  public chartColors: Array<any> = [
    { // first color
      backgroundColor: 'rgba(225,10,24,0.2)',
      borderColor: 'rgba(225,10,24,0.2)',
      pointBackgroundColor: 'rgba(225,10,24,0.2)',
      pointBorderColor: '#fff',
      pointHoverBackgroundColor: '#fff',
      pointHoverBorderColor: 'rgba(225,10,24,0.2)'
    },
    { // second color
      backgroundColor: 'rgba(225,10,24,0.2)',
      borderColor: 'rgba(225,10,24,0.2)',
      pointBackgroundColor: 'rgba(225,10,24,0.2)',
      pointBorderColor: '#fff',
      pointHoverBackgroundColor: '#fff',
      pointHoverBorderColor: 'rgba(225,10,24,0.2)'
    }];

Gray color is set by default, which means your color options don't work, because of wrong properties names.

Here you have an example, how colors properties are called:

ng2-charts-github-source-code

@UPDATE:

If there is a need to update just backgroundColor and nothing else, code below will work too.

public chartColors: Array<any> = [
    { // all colors in order
      backgroundColor: ['#d13537', '#b000b5', '#c0ffee', ...]
    }
]

Also you can do it in this way:

<base-chart class="chart"
            [colors]="chartColors"
            ...
</base-chart>

and

public chartColors: any[] = [
      { 
        backgroundColor:["#FF7360", "#6FC8CE", "#FAFFF2", "#FFFCC4", "#B9E8E0"] 
      }];