In the html, create a element:

<div id="sidebar-date"></div>

 

Add below script to footer or header:

<script>
const monthNames = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];

const d = new Date();

document.getElementById("sidebar-date").innerHTML = d.getDate()+" "+monthNames[d.getMonth()];
</script>