diff --git a/tsl/src/bgw_policy/continuous_aggregate_api.c b/tsl/src/bgw_policy/continuous_aggregate_api.c
index f967a5e2655..ce4af4bb8af 100644
--- a/tsl/src/bgw_policy/continuous_aggregate_api.c
+++ b/tsl/src/bgw_policy/continuous_aggregate_api.c
@@ -443,7 +443,7 @@ validate_window_size(const ContinuousAgg *cagg, const CaggPolicyConfig *config)
 		 * 2. Buckets with timezones
 		 * 3. Cases 1 and 2 at the same time
 		 *
-		 * For months we simply take 31 days as the worst case scenario and
+		 * For months we simply take 30 days like on interval_to_int64 and
 		 * multiply this number by the number of months in the bucket. This
 		 * reduces the task to days/hours/minutes scenario.
 		 *
@@ -459,7 +459,7 @@ validate_window_size(const ContinuousAgg *cagg, const CaggPolicyConfig *config)
 
 		/* Make a temporary copy of bucket_width */
 		Interval interval = *cagg->bucket_function->bucket_time_width;
-		interval.day += 31 * interval.month;
+		interval.day += 30 * interval.month;
 		interval.month = 0;
 		bucket_width = ts_interval_value_to_internal(IntervalPGetDatum(&interval), INTERVALOID);
 	}
diff --git a/tsl/test/expected/exp_cagg_monthly.out b/tsl/test/expected/exp_cagg_monthly.out
index 03cbe2278ac..d2d85aac584 100644
--- a/tsl/test/expected/exp_cagg_monthly.out
+++ b/tsl/test/expected/exp_cagg_monthly.out
@@ -1166,9 +1166,36 @@ ERROR:  policy refresh window too small
 SELECT add_continuous_aggregate_policy('conditions_summary_policy',
     start_offset => INTERVAL '65 days',
     end_offset => INTERVAL '1 day',
+    schedule_interval => INTERVAL '1 hour') AS job_id \gset
+SELECT delete_job(:job_id);
+ delete_job 
+------------
+ 
+(1 row)
+
+SELECT add_continuous_aggregate_policy('conditions_summary_policy',
+    start_offset => INTERVAL '2 months',
+    end_offset => INTERVAL '0 months',
+    schedule_interval => INTERVAL '1 hour') AS job_id \gset
+SELECT delete_job(:job_id);
+ delete_job 
+------------
+ 
+(1 row)
+
+\set ON_ERROR_STOP 0
+SELECT add_continuous_aggregate_policy('conditions_summary_policy',
+    start_offset => INTERVAL '2 months',
+    end_offset => INTERVAL '1 months',
+    schedule_interval => INTERVAL '1 hour');
+ERROR:  policy refresh window too small
+\set ON_ERROR_STOP 1
+SELECT add_continuous_aggregate_policy('conditions_summary_policy',
+    start_offset => INTERVAL '3 months',
+    end_offset => INTERVAL '1 months',
     schedule_interval => INTERVAL '1 hour');
  add_continuous_aggregate_policy 
 ---------------------------------
-                            1000
+                            1002
 (1 row)
 
diff --git a/tsl/test/sql/exp_cagg_monthly.sql b/tsl/test/sql/exp_cagg_monthly.sql
index dd792ce1fd6..ddfcb25d325 100644
--- a/tsl/test/sql/exp_cagg_monthly.sql
+++ b/tsl/test/sql/exp_cagg_monthly.sql
@@ -544,4 +544,25 @@ SELECT add_continuous_aggregate_policy('conditions_summary_policy',
 SELECT add_continuous_aggregate_policy('conditions_summary_policy',
     start_offset => INTERVAL '65 days',
     end_offset => INTERVAL '1 day',
+    schedule_interval => INTERVAL '1 hour') AS job_id \gset
+
+SELECT delete_job(:job_id);
+
+SELECT add_continuous_aggregate_policy('conditions_summary_policy',
+    start_offset => INTERVAL '2 months',
+    end_offset => INTERVAL '0 months',
+    schedule_interval => INTERVAL '1 hour') AS job_id \gset
+
+SELECT delete_job(:job_id);
+
+\set ON_ERROR_STOP 0
+SELECT add_continuous_aggregate_policy('conditions_summary_policy',
+    start_offset => INTERVAL '2 months',
+    end_offset => INTERVAL '1 months',
+    schedule_interval => INTERVAL '1 hour');
+\set ON_ERROR_STOP 1
+
+SELECT add_continuous_aggregate_policy('conditions_summary_policy',
+    start_offset => INTERVAL '3 months',
+    end_offset => INTERVAL '1 months',
     schedule_interval => INTERVAL '1 hour');