Delay Animations While Scrolling

Question

I'm trying to create animations as the user scrolls but I also want to stagger them in that they don't all happen at the same time but one after the other in quick succession.

I'm using the following which adds a class to the div which triggers css animations then I'm trying to use a setTimeout to delay the next animation by just a bit. I would think since it's in an $.each() loop it would hit each timeout but instead they all fade in at the time time...
JSFiddle

EDIT I believe I need to do this in JS as I have many animations on a page with a mixture of animations types and need to delay the adding of the class by a few milliseconds.

/**
 * Check if Animation is currently in view
 */
function anim_in_view() {
  var window_height = $(window).height();
  var window_top_position = $(window).scrollTop();
  var window_bottom_position = (window_top_position + window_height);
  var $animations = $('body .animate');

  if ($animations.length) {
    $.each($animations, function() {
      var $elm = $(this);
      var element_height = $elm.outerHeight();
      var element_top_position = $elm.offset().top + 50;
      var element_bottom_position = (element_top_position + element_height);

      setTimeout(function() {
        if ((element_bottom_position >= window_top_position) &&
          (element_top_position <= window_bottom_position)) {
          // $elm.delay( 2000 ).addClass( 'visible' );
          $elm.addClass('visible');
        }
      }, 1000);
    });
  }
}
$(window).on('load scroll resize', anim_in_view);

.flex {
  margin-top: 1000px;
  margin-bottom: 500px;
  display: -webkit-flex;
  display: flex;
}
.flex > div {
  width: 33.33%;
  height: 200px;
}
.red {
  background: #f00;
}
.green {
  background: #0f0;
}
.blue {
  background: #00f;
}
.animate-opacity {
  opacity: 0;
  -webkit-transition: opacity 1s ease-in-out;
  transition: opacity 2s ease-in-out;
}
.animate-opacity.visible {
  opacity: 1;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="fadeIns" class="flex">
  <div class="animate animate-opacity red"></div>
  <div class="animate animate-opacity green"></div>
  <div class="animate animate-opacity blue"></div>
</div>

Answer 1

You could use transition-delay to achieve this:

.animate-opacity:nth-child(2) {
  transition-delay: 1s;
}
.animate-opacity:nth-child(3) {
  transition-delay: 2s;
}

/**
 * Check if Animation is currently in view
 */
function anim_in_view() {
  var window_height = $(window).height();
  var window_top_position = $(window).scrollTop();
  var window_bottom_position = (window_top_position + window_height);
  var $animations = $('body .animate');

  if ($animations.length) {
    $.each($animations, function() {
      var $elm = $(this);
      var element_height = $elm.outerHeight();
      var element_top_position = $elm.offset().top + 50;
      var element_bottom_position = (element_top_position + element_height);

      if ((element_bottom_position >= window_top_position) &&
        (element_top_position <= window_bottom_position)) {
        // $elm.delay( 2000 ).addClass( 'visible' );
        $elm.addClass('visible');
      }
    });
  }
}
$(window).on('load scroll resize', anim_in_view);

.flex {
  margin-top: 1000px;
  margin-bottom: 500px;
  display: -webkit-flex;
  display: flex;
}
.flex > div {
  width: 33.33%;
  height: 200px;
}
.red {
  background: #f00;
}
.green {
  background: #0f0;
}
.blue {
  background: #00f;
}
.animate-opacity {
  opacity: 0;
  -webkit-transition: opacity 1s ease-in-out;
  transition: opacity 2s ease-in-out;
}
.animate-opacity:nth-child(2) {
  transition-delay: 1s;
}
.animate-opacity:nth-child(3) {
  transition-delay: 2s;
}
.animate-opacity.visible {
  opacity: 1;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="fadeIns" class="flex">
  <div class="animate animate-opacity red"></div>
  <div class="animate animate-opacity green"></div>
  <div class="animate animate-opacity blue"></div>
</div>