[Solved]-How to use decimal dates with Highcharts (such as 1992.9614)?-Highcharts

You can do this by using the xAxis.labels.formatter. You need to come up with a solution to parse your decimal year into more readable times. To do this I used the code from this answer. Sample code set:

function leapYear(year) {
  return ((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0);
}

function getMonthAndDayFromDayOfYear(dayOfYear, year) {
  var daysInMonthArray = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
  if (leapYear(year)) {
    daysInMonthArray[2] = 29;
  }

  var daysLeft = dayOfYear;
  var month = 0;
  for (i = 0; i < daysInMonthArray.length; i++) {
    var daysInThisMonth = daysInMonthArray[i];
    if (daysLeft > daysInThisMonth) {
      month += 1;
      daysLeft -= daysInThisMonth;
    } else {
      break;
    }
  }
  return {
    month: month,
    day: daysLeft
  };
}

function convertDecimalDate(decimalDate) {
  decimalDate = parseFloat(decimalDate);
  var year = parseInt(decimalDate); // Get just the integer part for the year
  var daysPerYear = leapYear(year) ? 366 : 365; // Set days per year based on leap year or not
  var decimalYear = decimalDate - year; // A decimal representing portion of the year left
  var dayOfYear = Math.ceil(decimalYear * daysPerYear); // day of Year: 1 to 355 (or 366)
  var md = getMonthAndDayFromDayOfYear(dayOfYear, year);
  var day = md['day'];
  var month = md['month'];
  return new Date(year, month, day);
}


Highcharts.chart('container', {
  chart: {
    type: 'column'
  },
  xAxis: {
    labels: {
      rotation: 45,
      formatter: function() {
        return convertDecimalDate(this.value);
      }
    }
  },
  tooltip: {
    formatter: function() {
      return '<b>' + this.series.name + '</b><br/>' +
        this.x + ': ' + this.y;
    }
  },
  series: [{
    data: [
      [2016.3610, 53.39000],
      [2016.3881, 53.29000],
      [2016.4153, 54.71000]
    ]
  }]
});

Live demo.

You can use the same method for the tooltip formatter as well. Note that I did not pick out a particular data time format as you did not specify what you need (month/year, or day/month, etc).