// Data retrieved https://en.wikipedia.org/wiki/List_of_cities_by_average_temperature
Highcharts.chart('container', {
    chart: {
        type: 'spline'
    },
    title: {
        text: 'Monthly Average Temperature'
    },
    subtitle: {
        text: 'Source: ' +
            '<a href="https://en.wikipedia.org/wiki/List_of_cities_by_average_temperature" ' +
            'target="_blank">Wikipedia.com</a>'
    },
    xAxis: {
        categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
            'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
        accessibility: {
            description: 'Months of the year'
        }
    },
    yAxis: {
        title: {
            text: 'Temperature'
        },
        labels: {
            formatter: function () {
                return this.value + '°';
            }
        }
    },
    tooltip: {
        crosshairs: true,
        shared: true
    },
    plotOptions: {
        spline: {
            marker: {
                radius: 4,
                lineColor: '#666666',
                lineWidth: 1
            }
        }
    },
    series: [{
        name: 'Tokyo',
        marker: {
            symbol: 'square'
        },
        data: [5.2, 5.7, 8.7, 13.9, 18.2, 21.4, 25.0, {
            y: 26.4,
            marker: {
                symbol: 'url(https://www.highcharts.com/samples/graphics/sun.png)'
            },
            accessibility: {
                description: 'Sunny symbol, this is the warmest point in the chart.'
            }
        }, 22.8, 17.5, 12.1, 7.6]

    }, {
        name: 'Bergen',
        marker: {
            symbol: 'diamond'
        },
        data: [{
            y: 1.5,
            marker: {
                symbol: 'url(https://www.highcharts.com/samples/graphics/snow.png)'
            },
            accessibility: {
                description: 'Snowy symbol, this is the coldest point in the chart.'
            }
        }, 1.6, 3.3, 5.9, 10.5, 13.5, 14.5, 14.4, 11.5, 8.7, 4.7, 2.6]
    }]
});