diff --git a/scripts/dashboards_render_atlas.py b/scripts/dashboards_render_atlas.py
index bd40f6e4..a2c61604 100644
--- a/scripts/dashboards_render_atlas.py
+++ b/scripts/dashboards_render_atlas.py
@@ -1442,7 +1442,7 @@ def build_overview():
             "decimals": 4,
             "text_mode": "value",
             "instant": True,
-            "description": "Rolling 365-day availability from vmalert's precomputed atlas:availability:ratio_365d series. Missing slots before the first raw availability sample are filled as 100% up; missing slots after that first sample count as down.",
+            "description": "Rolling 365-day availability from vmalert's precomputed atlas:availability:ratio_365d series. Missing slots before the first raw availability sample are filled as 100% up; observed down samples count as down, while scrape gaps are ignored.",
         },
         {
             "id": 4,
diff --git a/scripts/tests/test_dashboards_render_atlas.py b/scripts/tests/test_dashboards_render_atlas.py
index 9a9903a3..8e78bfbb 100644
--- a/scripts/tests/test_dashboards_render_atlas.py
+++ b/scripts/tests/test_dashboards_render_atlas.py
@@ -59,7 +59,7 @@ def test_overview_availability_panel_uses_recorded_365d_rollup():
     assert panel["targets"][0]["expr"] == 'last_over_time(atlas:availability:ratio_365d{scope="atlas"}[30m])'
     assert panel["targets"][0]["instant"] is True
     assert "precomputed" in panel["description"]
-    assert "after that first sample count as down" in panel["description"]
+    assert "scrape gaps are ignored" in panel["description"]
 
 
 def test_render_configmap_writes(tmp_path):
diff --git a/services/monitoring/dashboards/atlas-overview.json b/services/monitoring/dashboards/atlas-overview.json
index 641dad19..9df0eb83 100644
--- a/services/monitoring/dashboards/atlas-overview.json
+++ b/services/monitoring/dashboards/atlas-overview.json
@@ -283,7 +283,7 @@
         },
         "textMode": "value"
       },
-      "description": "Rolling 365-day availability from vmalert's precomputed atlas:availability:ratio_365d series. Missing slots before the first raw availability sample are filled as 100% up; missing slots after that first sample count as down."
+      "description": "Rolling 365-day availability from vmalert's precomputed atlas:availability:ratio_365d series. Missing slots before the first raw availability sample are filled as 100% up; observed down samples count as down, while scrape gaps are ignored."
     },
     {
       "id": 4,
diff --git a/services/monitoring/grafana-dashboard-overview.yaml b/services/monitoring/grafana-dashboard-overview.yaml
index 4a5b9606..3013cd35 100644
--- a/services/monitoring/grafana-dashboard-overview.yaml
+++ b/services/monitoring/grafana-dashboard-overview.yaml
@@ -292,7 +292,7 @@ data:
             },
             "textMode": "value"
           },
-          "description": "Rolling 365-day availability from vmalert's precomputed atlas:availability:ratio_365d series. Missing slots before the first raw availability sample are filled as 100% up; missing slots after that first sample count as down."
+          "description": "Rolling 365-day availability from vmalert's precomputed atlas:availability:ratio_365d series. Missing slots before the first raw availability sample are filled as 100% up; observed down samples count as down, while scrape gaps are ignored."
         },
         {
           "id": 4,
diff --git a/services/monitoring/vmalert-atlas-availability.yaml b/services/monitoring/vmalert-atlas-availability.yaml
index 549ffcb1..09a5cf29 100644
--- a/services/monitoring/vmalert-atlas-availability.yaml
+++ b/services/monitoring/vmalert-atlas-availability.yaml
@@ -81,7 +81,61 @@ data:
                   0
                 )
               )
-              / 8761, 1)
+              /
+              clamp_min(
+                (
+                  (
+                    sum(count_over_time((
+                      min(
+                        (
+                          sum(kube_node_status_condition{condition="Ready",status="true",node=~"titan-0a|titan-0b|titan-0c"})
+                          / 3
+                        ),
+                        (
+                          sum(kube_deployment_status_replicas_available{namespace=~"traefik|kube-system",deployment="traefik"})
+                          / clamp_min(sum(kube_deployment_spec_replicas{namespace=~"traefik|kube-system",deployment="traefik"}), 1)
+                        )
+                      )
+                    )[365d:1h]))
+                    or on() vector(0)
+                  )
+                  +
+                  clamp_min(
+                    8761
+                    -
+                    (
+                      clamp_min(
+                        floor(
+                          (
+                            time()
+                            -
+                            (
+                              min(min_over_time(timestamp(
+                                min(
+                                  (
+                                    sum(kube_node_status_condition{condition="Ready",status="true",node=~"titan-0a|titan-0b|titan-0c"})
+                                    / 3
+                                  ),
+                                  (
+                                    sum(kube_deployment_status_replicas_available{namespace=~"traefik|kube-system",deployment="traefik"})
+                                    / clamp_min(sum(kube_deployment_spec_replicas{namespace=~"traefik|kube-system",deployment="traefik"}), 1)
+                                  )
+                                )
+                              )[365d:1h]))
+                              or on() vector(time() + 3600)
+                            )
+                          )
+                          / 3600
+                        )
+                        + 1,
+                        0
+                      )
+                    ),
+                    0
+                  )
+                ),
+                1
+              ), 1)
             labels:
               scope: atlas
               rollup: yearly
@@ -114,7 +168,7 @@ spec:
       labels:
         app: vmalert-atlas-availability
       annotations:
-        bstein.dev/rules-revision: "2026-05-10-availability-rollup-v5"
+        bstein.dev/rules-revision: "2026-05-10-availability-rollup-v6"
     spec:
       serviceAccountName: vmalert-atlas-availability
       affinity: