Writing conditionals with moment js

Having some difficulty finding answers on how to do this.

date.text("Today's date is: " + moment().format("dddd MMM Do YY, h:mm a"));

Is what I am using to display the current time on the page. I am aiming to change some css depending on the time of day. I can't find a good example of how to do this. Ideally if it is after say 1PM the CSS would change.