diff --git a/.github/docs/openapi3.txt b/.github/docs/openapi3.txt
index 4729e0c3..47aaeadf 100644
--- a/.github/docs/openapi3.txt
+++ b/.github/docs/openapi3.txt
@@ -35,10 +35,10 @@ const (
 	FormatOfStringByte = `(^$|^[a-zA-Z0-9+/\-_]*=*$)`
 
 	// FormatOfStringDate is a RFC3339 date format regexp, for example "2017-07-21".
-	FormatOfStringDate = `^[0-9]{4}-(0[0-9]|10|11|12)-([0-2][0-9]|30|31)$`
+	FormatOfStringDate = `^[0-9]{4}-(0[1-9]|10|11|12)-(0[1-9]|[12][0-9]|3[01])$`
 
 	// FormatOfStringDateTime is a RFC3339 date-time format regexp, for example "2017-07-21T17:32:28Z".
-	FormatOfStringDateTime = `^[0-9]{4}-(0[0-9]|10|11|12)-([0-2][0-9]|30|31)T[0-9]{2}:[0-9]{2}:[0-9]{2}(\.[0-9]+)?(Z|(\+|-)[0-9]{2}:[0-9]{2})?$`
+	FormatOfStringDateTime = `^[0-9]{4}-(0[1-9]|10|11|12)-(0[1-9]|[12][0-9]|3[01])T([0-1][0-9]|2[0-3]):[0-5][0-9]:([0-5][0-9]|60)(\.[0-9]+)?(Z|(\+|-)[0-9]{2}:[0-9]{2})?$`
 )
 const (
 	SerializationSimple         = "simple"
diff --git a/openapi3/datetime_schema_test.go b/openapi3/datetime_schema_test.go
new file mode 100644
index 00000000..fec60576
--- /dev/null
+++ b/openapi3/datetime_schema_test.go
@@ -0,0 +1,167 @@
+package openapi3
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+var DateSpec = []byte(`
+components:
+  schemas:
+    Server:
+      properties:
+        date:
+          $ref: "#/components/schemas/timestamp"
+        name:
+          type: string
+      type: object
+    timestamp:
+      type: string
+      format: date
+openapi: "3.0.1"
+paths: {}
+info:
+  version: 1.1.1
+  title: title
+`[1:])
+
+var DateTimeSpec = []byte(`
+components:
+  schemas:
+    Server:
+      properties:
+        datetime:
+          $ref: "#/components/schemas/timestamp"
+        name:
+          type: string
+      type: object
+    timestamp:
+      type: string
+      format: date-time
+openapi: "3.0.1"
+paths: {}
+info:
+  version: 1.1.1
+  title: title
+`[1:])
+
+func TestDateZeroMonth(t *testing.T) {
+	loader := NewLoader()
+	doc, err := loader.LoadFromData(DateSpec)
+	require.NoError(t, err)
+
+	err = doc.Validate(loader.Context)
+	require.NoError(t, err)
+
+	err = doc.Components.Schemas["Server"].Value.VisitJSON(map[string]any{
+		"name": "kin-openapi",
+		"date": "2001-00-03",
+	})
+	require.EqualError(t, err, `Error at "/date": string doesn't match the format "date": string doesn't match pattern "`+FormatOfStringDate+`"`)
+}
+
+func TestDateZeroDay(t *testing.T) {
+	loader := NewLoader()
+	doc, err := loader.LoadFromData(DateSpec)
+	require.NoError(t, err)
+
+	err = doc.Validate(loader.Context)
+	require.NoError(t, err)
+
+	err = doc.Components.Schemas["Server"].Value.VisitJSON(map[string]any{
+		"name": "kin-openapi",
+		"date": "2001-02-00",
+	})
+	require.EqualError(t, err, `Error at "/date": string doesn't match the format "date": string doesn't match pattern "`+FormatOfStringDate+`"`)
+}
+
+func TestDateTimeZeroMonth(t *testing.T) {
+	loader := NewLoader()
+	doc, err := loader.LoadFromData(DateTimeSpec)
+	require.NoError(t, err)
+
+	err = doc.Validate(loader.Context)
+	require.NoError(t, err)
+
+	err = doc.Components.Schemas["Server"].Value.VisitJSON(map[string]any{
+		"name":     "kin-openapi",
+		"datetime": "2001-00-03T04:05:06.789Z",
+	})
+	require.EqualError(t, err, `Error at "/datetime": string doesn't match the format "date-time": string doesn't match pattern "`+FormatOfStringDateTime+`"`)
+}
+
+func TestDateTimeZeroDay(t *testing.T) {
+	loader := NewLoader()
+	doc, err := loader.LoadFromData(DateTimeSpec)
+	require.NoError(t, err)
+
+	err = doc.Validate(loader.Context)
+	require.NoError(t, err)
+
+	err = doc.Components.Schemas["Server"].Value.VisitJSON(map[string]any{
+		"name":     "kin-openapi",
+		"datetime": "2001-02-00T04:05:06.789Z",
+	})
+	require.EqualError(t, err, `Error at "/datetime": string doesn't match the format "date-time": string doesn't match pattern "`+FormatOfStringDateTime+`"`)
+}
+
+func TestDateTimeLeapSecond(t *testing.T) {
+	loader := NewLoader()
+	doc, err := loader.LoadFromData(DateTimeSpec)
+	require.NoError(t, err)
+
+	err = doc.Validate(loader.Context)
+	require.NoError(t, err)
+
+	err = doc.Components.Schemas["Server"].Value.VisitJSON(map[string]any{
+		"name":     "kin-openapi",
+		"datetime": "2016-12-31T23:59:60.000Z", // exact time of the most recent leap second
+	})
+	require.NoError(t, err)
+}
+
+func TestDateTimeHourOutOfBounds(t *testing.T) {
+	loader := NewLoader()
+	doc, err := loader.LoadFromData(DateTimeSpec)
+	require.NoError(t, err)
+
+	err = doc.Validate(loader.Context)
+	require.NoError(t, err)
+
+	err = doc.Components.Schemas["Server"].Value.VisitJSON(map[string]any{
+		"name":     "kin-openapi",
+		"datetime": "2016-12-31T24:00:00.000Z",
+	})
+	require.EqualError(t, err, `Error at "/datetime": string doesn't match the format "date-time": string doesn't match pattern "`+FormatOfStringDateTime+`"`)
+}
+
+func TestDateTimeMinuteOutOfBounds(t *testing.T) {
+	loader := NewLoader()
+	doc, err := loader.LoadFromData(DateTimeSpec)
+	require.NoError(t, err)
+
+	err = doc.Validate(loader.Context)
+	require.NoError(t, err)
+
+	err = doc.Components.Schemas["Server"].Value.VisitJSON(map[string]any{
+		"name":     "kin-openapi",
+		"datetime": "2016-12-31T23:60:00.000Z",
+	})
+	require.EqualError(t, err, `Error at "/datetime": string doesn't match the format "date-time": string doesn't match pattern "`+FormatOfStringDateTime+`"`)
+}
+
+func TestDateTimeSecondOutOfBounds(t *testing.T) {
+	loader := NewLoader()
+	doc, err := loader.LoadFromData(DateTimeSpec)
+	require.NoError(t, err)
+
+	err = doc.Validate(loader.Context)
+	require.NoError(t, err)
+
+	err = doc.Components.Schemas["Server"].Value.VisitJSON(map[string]any{
+		"name":     "kin-openapi",
+		"datetime": "2016-12-31T23:59:61.000Z",
+	})
+	require.EqualError(t, err, `Error at "/datetime": string doesn't match the format "date-time": string doesn't match pattern "`+FormatOfStringDateTime+`"`)
+}
diff --git a/openapi3/schema_formats.go b/openapi3/schema_formats.go
index 1b76707f..489105b4 100644
--- a/openapi3/schema_formats.go
+++ b/openapi3/schema_formats.go
@@ -41,10 +41,10 @@ const (
 	FormatOfStringByte = `(^$|^[a-zA-Z0-9+/\-_]*=*$)`
 
 	// FormatOfStringDate is a RFC3339 date format regexp, for example "2017-07-21".
-	FormatOfStringDate = `^[0-9]{4}-(0[0-9]|10|11|12)-([0-2][0-9]|30|31)$`
+	FormatOfStringDate = `^[0-9]{4}-(0[1-9]|10|11|12)-(0[1-9]|[12][0-9]|3[01])$`
 
 	// FormatOfStringDateTime is a RFC3339 date-time format regexp, for example "2017-07-21T17:32:28Z".
-	FormatOfStringDateTime = `^[0-9]{4}-(0[0-9]|10|11|12)-([0-2][0-9]|30|31)T[0-9]{2}:[0-9]{2}:[0-9]{2}(\.[0-9]+)?(Z|(\+|-)[0-9]{2}:[0-9]{2})?$`
+	FormatOfStringDateTime = `^[0-9]{4}-(0[1-9]|10|11|12)-(0[1-9]|[12][0-9]|3[01])T([0-1][0-9]|2[0-3]):[0-5][0-9]:([0-5][0-9]|60)(\.[0-9]+)?(Z|(\+|-)[0-9]{2}:[0-9]{2})?$`
 )
 
 func init() {
diff --git a/openapi3/schema_issue492_test.go b/openapi3/schema_issue492_test.go
index 2fdfcbce..15156722 100644
--- a/openapi3/schema_issue492_test.go
+++ b/openapi3/schema_issue492_test.go
@@ -46,5 +46,5 @@ info:
 		"name": "kin-openapi",
 		"time": "2001-02-03T04:05:06:789Z",
 	})
-	require.ErrorContains(t, err, `Error at "/time": string doesn't match the format "date-time": string doesn't match pattern "^[0-9]{4}-(0[0-9]|10|11|12)-([0-2][0-9]|30|31)T[0-9]{2}:[0-9]{2}:[0-9]{2}(\.[0-9]+)?(Z|(\+|-)[0-9]{2}:[0-9]{2})?$"`)
+	require.EqualError(t, err, `Error at "/time": string doesn't match the format "date-time": string doesn't match pattern "`+FormatOfStringDateTime+`"`)
 }