[Solved]-Vary font size in tick labels of time axis-d3.js

D3 doesn't provide anything to distinguish between the different types of ticks generated, but you can check the condition used in generating the labels in setting the styles as well. The code would look something like this.

d3.selectAll(".tick > text")
  .style("font-size", function(d) { return d.getHours() == 0 ? 32 : 24; });