diff --git a/src/weathergen/datasets/multi_stream_data_sampler.py b/src/weathergen/datasets/multi_stream_data_sampler.py
index 8449b053b..1cdd35c63 100644
--- a/src/weathergen/datasets/multi_stream_data_sampler.py
+++ b/src/weathergen/datasets/multi_stream_data_sampler.py
@@ -92,14 +92,6 @@ def __init__(
         self.batch_size = get_batch_size_from_config(mode_cfg)
         self.len_timedelta: np.timedelta64 = mode_cfg.time_window_len
         self.step_timedelta: np.timedelta64 = mode_cfg.time_window_step
-        self.time_window_handler = TimeWindowHandler(
-            mode_cfg.start_date, mode_cfg.end_date, self.len_timedelta, self.step_timedelta
-        )
-        if is_root():
-            logger.info(self.time_window_handler)
-
-        index_range = self.time_window_handler.get_index_range()
-        perms_len = int(index_range.end - index_range.start)
 
         # Handle forecast_delta_hrs which might be int (hours) or string (timedelta)
         self.forecast_cfg = mode_cfg.get("forecast", {})
@@ -125,6 +117,28 @@ def __init__(
 
         fsm = self.list_num_forecast_steps[0]
         forecast_len = (self.time_step * (fsm + 1)) // self.step_timedelta
+
+        # Handle too short time window causing duplication of samples
+        available_samples = (mode_cfg.end_date - mode_cfg.start_date) // self.time_step
+        if self.samples_per_mini_epoch >= available_samples:
+            # padding to widen time window
+            samples_diff = (
+                self.samples_per_mini_epoch - available_samples + forecast_len + 1
+            )  # extra step to be safe
+            new_end_date = mode_cfg.end_date + (samples_diff * self.time_step)
+            logger.warning(f"Using adjusted end date {new_end_date} instead of {mode_cfg.end_date}")
+            self.time_window_handler = TimeWindowHandler(
+                mode_cfg.start_date, new_end_date, self.len_timedelta, self.step_timedelta
+            )
+        else:
+            self.time_window_handler = TimeWindowHandler(
+                mode_cfg.start_date, mode_cfg.end_date, self.len_timedelta, self.step_timedelta
+            )
+        if is_root():
+            logger.info(self.time_window_handler)
+
+        index_range = self.time_window_handler.get_index_range()
+        perms_len = int(index_range.end - index_range.start)
         perms_len = perms_len - (forecast_len + self.output_offset)
 
         self.repeat_data = cf.data_loading.get("repeat_data_in_mini_epoch", False)