diff --git a/core/lib/Drupal/Core/Datetime/Element/DateElementBase.php b/core/lib/Drupal/Core/Datetime/Element/DateElementBase.php
index 63b9abb871..433cdf8b18 100644
--- a/core/lib/Drupal/Core/Datetime/Element/DateElementBase.php
+++ b/core/lib/Drupal/Core/Datetime/Element/DateElementBase.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Core\Datetime\Element;
 
+use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Datetime\DrupalDateTime;
 use Drupal\Core\Render\Element\FormElement;
 
@@ -69,4 +70,36 @@ protected static function datetimeRangeYears($string, $date = NULL) {
     return [$min_year, $max_year];
   }
 
+  /**
+   * Returns the most relevant title of a datetime element.
+   *
+   * Since datetime form elements often consist of combined date and time fields
+   * the element title might not be located on the element itself but on the
+   * parent container element.
+   *
+   * @param array $element
+   *   The element being processed.
+   * @param array $complete_form
+   *   The complete form structure.
+   *
+   * @return string
+   *   The title.
+   */
+  protected static function getElementTitle($element, $complete_form) {
+    $title = '';
+    if (!empty($element['#title'])) {
+      $title = $element['#title'];
+    }
+    else {
+      $parents = $element['#array_parents'];
+      array_pop($parents);
+      $parent_element = NestedArray::getValue($complete_form, $parents);
+      if (!empty($parent_element['#title'])) {
+        $title = $parent_element['#title'];
+      }
+    }
+
+    return $title;
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Datetime/Element/Datelist.php b/core/lib/Drupal/Core/Datetime/Element/Datelist.php
index 59177e77e9..6f110d395f 100644
--- a/core/lib/Drupal/Core/Datetime/Element/Datelist.php
+++ b/core/lib/Drupal/Core/Datetime/Element/Datelist.php
@@ -302,6 +302,8 @@ public static function processDatelist(&$element, FormStateInterface $form_state
   public static function validateDatelist(&$element, FormStateInterface $form_state, &$complete_form) {
     $input_exists = FALSE;
     $input = NestedArray::getValue($form_state->getValues(), $element['#parents'], $input_exists);
+    $title = static::getElementTitle($element, $complete_form);
+
     if ($input_exists) {
       $all_empty = static::checkEmptyInputs($input, $element['#date_part_order']);
 
@@ -311,10 +313,11 @@ public static function validateDatelist(&$element, FormStateInterface $form_stat
       }
       // If there's empty input and the field is required, set an error.
       elseif (empty($input['year']) && empty($input['month']) && empty($input['day']) && $element['#required']) {
-        $form_state->setError($element, t('The %field date is required.'));
+        $form_state->setError($element, t('The %field date is required.', ['%field' => $title]));
       }
       elseif (!empty($all_empty)) {
         foreach ($all_empty as $value) {
+          $form_state->setError($element, t('The %field date is incomplete.', ['%field' => $title]));
           $form_state->setError($element[$value], t('A value must be selected for %part.', ['%part' => $value]));
         }
       }
@@ -326,7 +329,7 @@ public static function validateDatelist(&$element, FormStateInterface $form_stat
         }
         // If the input is invalid and an error doesn't exist, set one.
         elseif ($form_state->getError($element) === NULL) {
-          $form_state->setError($element, t('The %field date is invalid.', ['%field' => !empty($element['#title']) ? $element['#title'] : '']));
+          $form_state->setError($element, t('The %field date is invalid.', ['%field' => $title]));
         }
       }
     }
diff --git a/core/modules/datetime/tests/src/Functional/DateTestBase.php b/core/modules/datetime/tests/src/Functional/DateTestBase.php
index 369e793343..9127eb25d4 100644
--- a/core/modules/datetime/tests/src/Functional/DateTestBase.php
+++ b/core/modules/datetime/tests/src/Functional/DateTestBase.php
@@ -107,6 +107,7 @@ protected function setUp() {
    */
   protected function createField() {
     $field_name = Unicode::strtolower($this->randomMachineName());
+    $field_label = Unicode::ucfirst(Unicode::strtolower($this->randomMachineName()));
     $type = $this->getTestFieldType();
     $widget_type = $formatter_type = $type . '_default';
 
@@ -119,8 +120,9 @@ protected function createField() {
     $this->fieldStorage->save();
     $this->field = FieldConfig::create([
       'field_storage' => $this->fieldStorage,
+      'label' => $field_label,
       'bundle' => 'entity_test',
-      'description' => 'Description for ' . $field_name,
+      'description' => 'Description for ' . $field_label,
       'required' => TRUE,
     ]);
     $this->field->save();
diff --git a/core/modules/datetime/tests/src/Functional/DateTimeFieldTest.php b/core/modules/datetime/tests/src/Functional/DateTimeFieldTest.php
index ab03ff5772..3df2582e3e 100644
--- a/core/modules/datetime/tests/src/Functional/DateTimeFieldTest.php
+++ b/core/modules/datetime/tests/src/Functional/DateTimeFieldTest.php
@@ -208,6 +208,7 @@ public function testDateField() {
    */
   public function testDatetimeField() {
     $field_name = $this->fieldStorage->getName();
+    $field_label = $this->field->label();
     // Change the field to a datetime field.
     $this->fieldStorage->setSetting('datetime_type', 'datetime');
     $this->fieldStorage->save();
@@ -216,7 +217,7 @@ public function testDatetimeField() {
     $this->drupalGet('entity_test/add');
     $this->assertFieldByName("{$field_name}[0][value][date]", '', 'Date element found.');
     $this->assertFieldByName("{$field_name}[0][value][time]", '', 'Time element found.');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_label, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -352,6 +353,7 @@ public function testDatetimeField() {
    */
   public function testDatelistWidget() {
     $field_name = $this->fieldStorage->getName();
+    $field_label = $this->field->label();
 
     // Ensure field is set to a date only field.
     $this->fieldStorage->setSetting('datetime_type', 'date');
@@ -370,7 +372,7 @@ public function testDatelistWidget() {
 
     // Display creation form.
     $this->drupalGet('entity_test/add');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_label, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -511,7 +513,7 @@ public function testDatelistWidget() {
     \Drupal::entityManager()->clearCachedFieldDefinitions();
 
     // Test the widget for validation notifications.
-    foreach ($this->datelistDataProvider() as $data) {
+    foreach ($this->datelistDataProvider($field_label) as $data) {
       list($date_value, $expected) = $data;
 
       // Display creation form.
@@ -562,13 +564,21 @@ public function testDatelistWidget() {
   /**
    * The data provider for testing the validation of the datelist widget.
    *
+   * @param string $field_label
+   *   The label of the field being tested.
+   *
    * @return array
    *   An array of datelist input permutations to test.
    */
-  protected function datelistDataProvider() {
+  protected function datelistDataProvider($field_label) {
     return [
+      // Nothing selected.
+      [['year' => '', 'month' => '', 'day' => '', 'hour' => '', 'minute' => ''], [
+        "The $field_label date is required.",
+      ]],
       // Year only selected, validation error on Month, Day, Hour, Minute.
       [['year' => 2012, 'month' => '', 'day' => '', 'hour' => '', 'minute' => ''], [
+        "The $field_label date is incomplete.",
         'A value must be selected for month.',
         'A value must be selected for day.',
         'A value must be selected for hour.',
@@ -576,17 +586,20 @@ protected function datelistDataProvider() {
       ]],
       // Year and Month selected, validation error on Day, Hour, Minute.
       [['year' => 2012, 'month' => '12', 'day' => '', 'hour' => '', 'minute' => ''], [
+        "The $field_label date is incomplete.",
         'A value must be selected for day.',
         'A value must be selected for hour.',
         'A value must be selected for minute.',
       ]],
       // Year, Month and Day selected, validation error on Hour, Minute.
       [['year' => 2012, 'month' => '12', 'day' => '31', 'hour' => '', 'minute' => ''], [
+        "The $field_label date is incomplete.",
         'A value must be selected for hour.',
         'A value must be selected for minute.',
       ]],
       // Year, Month, Day and Hour selected, validation error on Minute only.
       [['year' => 2012, 'month' => '12', 'day' => '31', 'hour' => '0', 'minute' => ''], [
+        "The $field_label date is incomplete.",
         'A value must be selected for minute.',
       ]],
     ];
diff --git a/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php b/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
index 23ba8fab03..685da99387 100644
--- a/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
+++ b/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
@@ -46,6 +46,7 @@ protected function getTestFieldType() {
    */
   public function testDateRangeField() {
     $field_name = $this->fieldStorage->getName();
+    $field_label = $this->field->label();
 
     // Loop through defined timezones to test that date-only fields work at the
     // extremes.
@@ -64,7 +65,7 @@ public function testDateRangeField() {
       $this->assertFieldByXPath('//*[@id="edit-' . $field_name . '-wrapper"]//label[contains(@class, "js-form-required")]', TRUE, 'Required markup found');
       $this->assertNoFieldByName("{$field_name}[0][value][time]", '', 'Start time element not found.');
       $this->assertNoFieldByName("{$field_name}[0][end_value][time]", '', 'End time element not found.');
-      $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
+      $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_label, 'Fieldset and label found');
       $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
       $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -256,6 +257,7 @@ public function testDateRangeField() {
    */
   public function testDatetimeRangeField() {
     $field_name = $this->fieldStorage->getName();
+    $field_label = $this->field->label();
 
     // Ensure the field to a datetime field.
     $this->fieldStorage->setSetting('datetime_type', DateRangeItem::DATETIME_TYPE_DATETIME);
@@ -267,7 +269,7 @@ public function testDatetimeRangeField() {
     $this->assertFieldByName("{$field_name}[0][value][time]", '', 'Start time element found.');
     $this->assertFieldByName("{$field_name}[0][end_value][date]", '', 'End date element found.');
     $this->assertFieldByName("{$field_name}[0][end_value][time]", '', 'End time element found.');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_label, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -428,6 +430,7 @@ public function testDatetimeRangeField() {
    */
   public function testAlldayRangeField() {
     $field_name = $this->fieldStorage->getName();
+    $field_label = $this->field->label();
 
     // Ensure field is set to a all-day field.
     $this->fieldStorage->setSetting('datetime_type', DateRangeItem::DATETIME_TYPE_ALLDAY);
@@ -440,7 +443,7 @@ public function testAlldayRangeField() {
     $this->assertFieldByXPath('//*[@id="edit-' . $field_name . '-wrapper"]//label[contains(@class, "js-form-required")]', TRUE, 'Required markup found');
     $this->assertNoFieldByName("{$field_name}[0][value][time]", '', 'Start time element not found.');
     $this->assertNoFieldByName("{$field_name}[0][end_value][time]", '', 'End time element not found.');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_label, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');
 
@@ -598,6 +601,7 @@ public function testAlldayRangeField() {
    */
   public function testDatelistWidget() {
     $field_name = $this->fieldStorage->getName();
+    $field_label = $this->field->label();
 
     // Ensure field is set to a date only field.
     $this->fieldStorage->setSetting('datetime_type', DateRangeItem::DATETIME_TYPE_DATE);
@@ -616,7 +620,7 @@ public function testDatelistWidget() {
 
     // Display creation form.
     $this->drupalGet('entity_test/add');
-    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_name, 'Fieldset and label found');
+    $this->assertFieldByXPath('//fieldset[@id="edit-' . $field_name . '-0"]/legend', $field_label, 'Fieldset and label found');
     $this->assertFieldByXPath('//fieldset[@aria-describedby="edit-' . $field_name . '-0--description"]', NULL, 'ARIA described-by found');
     $this->assertFieldByXPath('//div[@id="edit-' . $field_name . '-0--description"]', NULL, 'ARIA description found');