[Solved]-how do you change the color of cells in highcharts heatmap?-Highcharts

You need to use Highcharts 3.0.10, to set colours.

        stops: [

        [0, '#FF0000'],
       [1, '#00FF00'],
       [2, '#FFA500'],
       [3,'#FFFF00']

    ],
        min: 0,
        max: 1

This will give you the exact colours also in the series you need to give the json Object like this: {"x":0,"y":0,"value":0,"myData":"Critical"} The value is the attribute which gives exact colour

Use colors for list of colors,

In colorAxis declare dataClassColor as 'category' and define your data range in dataClasses

colors : ['#D7EDE5', '#9BD1BE', '#37A47E'],

colorAxis : {
    dataClassColor : 'category',
    dataClasses : [{
            to : 57.1
        }, {
            from : 57.2,
            to : 60.4
        }, {
            from : 60.5
        }
    ]
},

Demo http://jsfiddle.net/patelriki13/q2yww0vw/