The option borderDash on gridlines seems to be ignored for polar area charts.
making the grid solid instead.
config:
{
type: "polarArea",
data: {
datasets: [{
data: [10, 20, 30]
}],
labels: [
'Red',
'Yellow',
'Blue'
]
},
options: {
scale: {
gridLines:{
lineWidth: 2,
borderDash:[4,5]
}
}
}
}
fiddle
https://jsfiddle.net/u7tt00bu/