score:1

Accepted answer

You're closing the tbody before the last value (HINDCAST - SPREAD), once put outside the for loop it works :

...
    tooltip += '<tr><th style="font-size: 14px; color: ' + point.series.color + '">' + point.series.name + ': </th>' +
               '<td style="font-size: 14px">' + point.point.low + '℃ -' + point.point.high + '℃' + '</td></tr>'
    }
});
tooltip += '</tbody></table>';
return tooltip;
...

Fiddle


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