diff --git a/core/lib/Drupal/Core/Datetime/DrupalDateTime.php b/core/lib/Drupal/Core/Datetime/DrupalDateTime.php
index 9f9edc4739..1ed95fdb17 100644
--- a/core/lib/Drupal/Core/Datetime/DrupalDateTime.php
+++ b/core/lib/Drupal/Core/Datetime/DrupalDateTime.php
@@ -25,7 +25,7 @@ class DrupalDateTime extends DateTimePlus {
   /**
    * Format string translation cache.
    *
-   * @var string
+   * @var array
    */
   protected $formatTranslationCache;