use time.Format to format dates. It allows dates to be localized.

README.md

@@ -287,7 +287,7 @@ Dates of blog posts and single pages are rendered with the default date format c
   date_format = "2. January 2006"
 ```
 
-See hugo's documentation of the [`dateFormat` function](https://gohugo.io/functions/dateformat/) for more details.
+See hugo's documentation of the [`time.Format` function](https://gohugo.io/functions/dateformat/) for more details.
 
 
 ### Nearly finished

layouts/_default/single.html

@@ -32,7 +32,7 @@ <h1 class="f1 athelas mt3 mb1">
       {{/* Hugo uses Go's date formatting is set by example. Here are two formats */}}
       {{ if not .Date.IsZero }}
       <time class="f6 mv4 dib tracked" {{ printf `datetime="%s"` (.Date.Format "2006-01-02T15:04:05Z07:00") | safeHTMLAttr }}>
-        {{- .Date.Format (default "January 2, 2006" .Site.Params.date_format) -}}
+        {{- .Date | time.Format (default ":date_full" .Site.Params.date_format) -}}
       </time>
       {{end}}
 

layouts/post/summary.html

@@ -1,7 +1,7 @@
   <div class="mb3 pa4 {{ $.Param "text_color" | default "mid-gray" }} overflow-hidden">
     {{ if .Date }}
       <div class="f6">
-        {{ .Date.Format (default "January 2, 2006" .Site.Params.date_format) }}
+        {{ .Date | time.Format (default ":date_full" .Site.Params.date_format) }}
       </div>
     {{ end }}
     <h1 class="f3 near-black">