Datepicker in semantic ui

Yes there is, you'll have to give your input a type attribute of date,

<input type="date">

This is how it looks like

Take a look on this Semantic UI Calendar module which results from the above mentioned pull request. Lots of customization and looks nice.

<h3>Input</h3>
<div class="ui calendar" id="example1">
  <div class="ui input left icon">
    <i class="calendar icon"></i>
    <input type="text" placeholder="Date/Time">
  </div>
</div>

and

$('#example1').calendar();

At this time of writing, there is a pending pull request here:

https://github.com/Semantic-Org/Semantic-UI/pull/3256

Here is how it looks

https://jsbin.com/hubanufuva/1/edit?html,js,output