diff --git a/src/js/storage.js b/src/js/storage.js
index 627d6a7e9..78ddeb575 100644
--- a/src/js/storage.js
+++ b/src/js/storage.js
@@ -765,9 +765,12 @@
         }
     }
     // Extract update frequency information
-    matches = head.match(/(?:^|\n)(?:!|# )[\t ]*Expires:[\t ]*(\d+)[\t ]*day/i);
+    matches = head.match(/(?:^|\n)(?:!|# )[\t ]*Expires:[\t ]*(\d+)[\t ]*(day|hour)/i);
     if ( matches !== null ) {
         v = Math.max(parseInt(matches[1], 10), 1);
+        if ( matches[2].toLowerCase() === 'hour' ) {
+            v = Math.ceil(v / 24);
+        }
         if ( v !== listEntry.updateAfter ) {
             this.assets.registerAssetSource(assetKey, { updateAfter: v });
         }