diff --git a/src/itzi_core/simulation.py b/src/itzi_core/simulation.py
index a5286c9..583d096 100644
--- a/src/itzi_core/simulation.py
+++ b/src/itzi_core/simulation.py
@@ -564,11 +564,13 @@ def reconcile_hotstart_resume(self, hotstart_config: SimulationConfig) -> Self:
             if not self.drainage_model:
                 self.schedule.set_deadline("drainage", self.end_time)
 
+        # Accumulators begin at the last archived report boundary, independently
+        # of the cadence selected for the resumed run.
+        self.report.last_step = self.schedule.deadline("record") - hotstart_config.record_step
         if self.report.dt != hotstart_config.record_step:
             self.schedule.set_deadline(
                 "record", min(self.end_time, self.sim_time + self.report.dt)
             )
-            self.report.last_step = copy.copy(self.sim_time)
 
         if self.hydrology_model.dt != timedelta(seconds=hotstart_config.dtinf):
             self.schedule.set_deadline(
diff --git a/tests/test_hotstart_integration.py b/tests/test_hotstart_integration.py
index 087255b..1aa39dc 100644
--- a/tests/test_hotstart_integration.py
+++ b/tests/test_hotstart_integration.py
@@ -74,7 +74,7 @@ def create_sim_config(
         ),
         output_map_names=helpers.make_output_map_names(
             "out_hotstart",
-            ["water_depth", "qx", "qy", "created_volume"],
+            ["water_depth", "qx", "qy", "created_volume", "mean_rainfall"],
         ),
         surface_flow_parameters=SurfaceFlowParameters(hmin=0.0001, dtmax=0.3, cfl=0.2),
         infiltration_model=InfiltrationModelType.GREEN_AMPT,
@@ -351,6 +351,15 @@ def test_roundtrip_state_restoration_and_match(
     # Calling initialize() would overwrite restored state (old_domain_volume, accum arrays, etc.)
     run_simulation_to_end(sim_b, skip_initialize=True)
 
+    resumed_output = sim_b.report.raster_provider
+    assert isinstance(resumed_output, MemoryRasterOutputProvider)
+    _, mean_rainfall = resumed_output.output_maps_dict["mean_rainfall"][0]
+    np.testing.assert_allclose(
+        mean_rainfall,
+        domain_5by5.arr_rain * 3_600_000,
+        rtol=1e-5,
+    )
+
     # Step 4: Verify final results match uninterrupted reference
     # Use qe/qs (internal flow arrays) instead of qx/qy (output arrays computed on-the-fly)
     assert_final_state_matches(sim_b, uninterrupted_simulation)
@@ -472,6 +481,12 @@ def test_resume_applies_new_record_step_cadence(
     ]
 
     assert resumed_record_times[: len(expected_record_times)] == expected_record_times
+    _, mean_rainfall = resumed_output.output_maps_dict["mean_rainfall"][0]
+    np.testing.assert_allclose(
+        mean_rainfall,
+        domain_5by5.arr_rain * 3_600_000,
+        rtol=1e-5,
+    )
 
     assert_state_differs(sim_b, record_step_hotstart_run["simulation"])