diff --git a/app/code/Magento/Customer/Test/Unit/Block/Widget/DobTest.php b/app/code/Magento/Customer/Test/Unit/Block/Widget/DobTest.php
index 1fd7fc340e542..d793b864e0e79 100644
--- a/app/code/Magento/Customer/Test/Unit/Block/Widget/DobTest.php
+++ b/app/code/Magento/Customer/Test/Unit/Block/Widget/DobTest.php
@@ -48,7 +48,7 @@ class DobTest extends TestCase
     const YEAR = '2014';
 
     // Value of date('Y', strtotime(self::DATE))
-    const DATE_FORMAT = 'M/d/Y';
+    const DATE_FORMAT = 'M/dd/Y';
 
     /** Constants used by Dob::setDateInput($code, $html) */
     const DAY_HTML =
@@ -357,8 +357,8 @@ public function getDateFormatDataProvider(): array
             [
                 'ar_SA',
                 preg_replace(
-                    '/[^MmDdYy\/\.\-]/',
-                    '',
+                    ['/[^MmDdYy\/\.\-]/','/d+/'],
+                    ['','dd'],
                     (new \IntlDateFormatter('ar_SA', \IntlDateFormatter::SHORT, \IntlDateFormatter::NONE))
                         ->getPattern()
                 )
@@ -544,8 +544,8 @@ public function testGetHtmlExtraParamsWithoutRequiredOption()
     {
         $this->escaper->expects($this->any())
             ->method('escapeHtml')
-            ->with('{"validate-date":{"dateFormat":"M\/d\/Y"},"validate-dob":true}')
-            ->will($this->returnValue('{"validate-date":{"dateFormat":"M\/d\/Y"},"validate-dob":true}'));
+            ->with('{"validate-date":{"dateFormat":"M\/dd\/Y"},"validate-dob":true}')
+            ->will($this->returnValue('{"validate-date":{"dateFormat":"M\/dd\/Y"},"validate-dob":true}'));
 
         $this->attribute->expects($this->once())
             ->method("isRequired")
@@ -553,7 +553,7 @@ public function testGetHtmlExtraParamsWithoutRequiredOption()
 
         $this->assertEquals(
             $this->_block->getHtmlExtraParams(),
-            'data-validate="{"validate-date":{"dateFormat":"M\/d\/Y"},"validate-dob":true}"'
+            'data-validate="{"validate-date":{"dateFormat":"M\/dd\/Y"},"validate-dob":true}"'
         );
     }
 
@@ -567,17 +567,17 @@ public function testGetHtmlExtraParamsWithRequiredOption()
             ->willReturn(true);
         $this->escaper->expects($this->any())
             ->method('escapeHtml')
-            ->with('{"required":true,"validate-date":{"dateFormat":"M\/d\/Y"},"validate-dob":true}')
+            ->with('{"required":true,"validate-date":{"dateFormat":"M\/dd\/Y"},"validate-dob":true}')
             ->will(
                 $this->returnValue(
-                    '{"required":true,"validate-date":{"dateFormat":"M\/d\/Y"},"validate-dob":true}'
+                    '{"required":true,"validate-date":{"dateFormat":"M\/dd\/Y"},"validate-dob":true}'
                 )
             );
 
         $this->context->expects($this->any())->method('getEscaper')->will($this->returnValue($this->escaper));
 
         $this->assertEquals(
-            'data-validate="{"required":true,"validate-date":{"dateFormat":"M\/d\/Y"},"validate-dob":true}"',
+            'data-validate="{"required":true,"validate-date":{"dateFormat":"M\/dd\/Y"},"validate-dob":true}"',
             $this->_block->getHtmlExtraParams()
         );
     }
diff --git a/lib/internal/Magento/Framework/Stdlib/DateTime/Timezone.php b/lib/internal/Magento/Framework/Stdlib/DateTime/Timezone.php
index 0791c89ab793a..0b6d84beb5951 100644
--- a/lib/internal/Magento/Framework/Stdlib/DateTime/Timezone.php
+++ b/lib/internal/Magento/Framework/Stdlib/DateTime/Timezone.php
@@ -130,8 +130,8 @@ public function getDateFormat($type = \IntlDateFormatter::SHORT)
     public function getDateFormatWithLongYear()
     {
         return preg_replace(
-            '/(?<!y)yy(?!y)/',
-            'Y',
+            ['/(?<!y)yy(?!y)/','/d+/'],
+            ['Y','dd'],
             $this->getDateFormat()
         );
     }