Сделал виджет с переопределением 4 главных функций календаря в js

backend/modules/card/models/UserCardSearch.php

@@ -6,7 +6,6 @@ use common\classes\Debug;
 use Yii;
 use yii\base\Model;
 use yii\data\ActiveDataProvider;
-use backend\modules\card\models\UserCard;
 
 /**
  * UserCardSearch represents the model behind the search form of `backend\modules\card\models\UserCard`.
@@ -64,6 +63,10 @@ class UserCardSearch extends UserCard
 
         $query->where(['deleted_at' => null]);
 
+        if (isset($params['month'])) {
+            $query->andFilterWhere(['=', 'MONTH(dob)', $params['month']]);
+        }
+
         // grid filtering conditions
         $query->andFilterWhere([
             'id' => $this->id,