diff --git a/_layouts/single.html b/_layouts/single.html
index 2a33c273..e60b8dc7 100644
--- a/_layouts/single.html
+++ b/_layouts/single.html
@@ -20,8 +20,8 @@ layout: default
   <article class="page" itemscope itemtype="https://schema.org/CreativeWork">
     {% if page.title %}<meta itemprop="headline" content="{{ page.title | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.excerpt %}<meta itemprop="description" content="{{ page.excerpt | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
-    {% if page.date %}<meta itemprop="datePublished" content="{{ page.date | date: "%B %d, %Y" }}">{% endif %}
-    {% if page.last_modified_at %}<meta itemprop="dateModified" content="{{ page.last_modified_at | date: "%B %d, %Y" }}">{% endif %}
+    {% if page.date %}<meta itemprop="datePublished" content="{{ page.date | date_to_xmlschema }}">{% endif %}
+    {% if page.last_modified_at %}<meta itemprop="dateModified" content="{{ page.last_modified_at | date_to_xmlschema }}">{% endif %}
 
     <div class="page__inner-wrap">
       {% unless page.header.overlay_color or page.header.overlay_image %}
diff --git a/_layouts/splash.html b/_layouts/splash.html
index b327607e..21165024 100644
--- a/_layouts/splash.html
+++ b/_layouts/splash.html
@@ -12,8 +12,8 @@ layout: default
   <article class="splash" itemscope itemtype="https://schema.org/CreativeWork">
     {% if page.title %}<meta itemprop="headline" content="{{ page.title | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.excerpt %}<meta itemprop="description" content="{{ page.excerpt | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
-    {% if page.date %}<meta itemprop="datePublished" content="{{ page.date | date: "%B %d, %Y" }}">{% endif %}
-    {% if page.last_modified_at %}<meta itemprop="dateModified" content="{{ page.last_modified_at | date: "%B %d, %Y" }}">{% endif %}
+    {% if page.date %}<meta itemprop="datePublished" content="{{ page.date | date_to_xmlschema }}">{% endif %}
+    {% if page.last_modified_at %}<meta itemprop="dateModified" content="{{ page.last_modified_at | date_to_xmlschema }}">{% endif %}
 
     <section class="page__content" itemprop="text">
       {{ content }}