diff --git a/hosts/hass.windy.lan.md b/hosts/hass.windy.lan.md
index de7b4b2..716829b 100644
--- a/hosts/hass.windy.lan.md
+++ b/hosts/hass.windy.lan.md
@@ -228,6 +228,54 @@ cost/ladder sensors can stay `unknown` because CSG
 dashboard uses template ladder/cost entities instead. Do not change
 `templates/csg_sensors.yaml` or the 电力监控 dashboard for an install.
 
+**`templates/csg_sensors.yaml` hardened 2026-08-29 (W1N-239):** added
+`availability` templates to all 12 `csg_*` sensors (numeric sensors can't
+render `unknown`/`unavailable` in `state`; availability suppresses
+rendering instead — native CSG down ⇒ derived sensors show `unavailable`,
+no more fake zeros / "一档" / `0%`). `csg_yesterday_kwh` now falls back to
+`last_month_by_day`'s last entry when `this_month_by_day` is empty (month
+start); ladder constants (`t1/t2/p1/p2/p3`) deduped into per-block
+`variables:` (Block B + Block D); `csg_mom_change` parses `date`
+defensively. Backup:
+`/homeassistant/.csg-backups/csg_sensors.yaml.bak-20260829-w1n239`.
+**Verified:** `ha core check` OK; Core restart required (trigger-based
+template blocks don't settle on `template.reload` — W1N-114 precedent);
+post-restart all 12 entities numeric & consistent (302.47 kWh→180.28 元,
+324.03 kWh→194.06 元, mom_change -3.6%, yesterday 7.66 kWh/2026-08-28),
+no template errors in Core logs.
+
+**`csg_sensors.yaml` off-by-one fixed 2026-08-29 (W1N-241):** CSG data
+lags 1 day (`sum(this_month_by_day)` == `this_month_total_usage`, data
+stops at yesterday), but templates used `now().day` as "days elapsed" →
+`csg_predicted_usage` underestimated ~1 daily avg (~3%) and
+`csg_mom_change` compared this-month 28 days vs last-month 29 days
+(-3.6% vs true -0.3%). Both now derive the day number from
+`this_month_by_day[-1].date` (fallback `now().day` when empty). Added
+`sensor.csg_this_month_daily_avg` (month-to-date avg, 302.47/28=10.8) and
+`sensor.csg_prediction_progress` (usage/predicted %, 90.3) in Block C
+(trigger adds `csg_predicted_usage`). Backup:
+`/homeassistant/.csg-backups/csg_sensors.yaml.bak-20260829-w1n241`.
+**Verified (8/29):** predicted 324.03→334.81, mom_change -3.6→-0.3,
+daily_avg 10.8, progress 90.3, predicted_cost 194.06→200.94 (334.81 kWh
+ladder), ladder cost 180.28 unchanged, `ha core check` OK after restart,
+no template errors; 14 csg_* entities total.
+
+**电力监控面板（`lovelace.dashboard_unknown` / view `power-monitor`）
+updated 2026-08-29 (W1N-240):** 「本月累计」gauge 对齐夏季阶梯：
+`max:650`、segments `0/260/600`（绿/橙/红 = 一/二/三档；冬季 11-01 需切
+`max:450`、`0/200/400` — **seasonal switch point**，见下文）。「📊 统计
+数据」卡新增本年/去年 4 行（原生传感器，口径标注「电费(账单)」、本年
+「(至今)」）；面板共引用 18 个实体。改前备份：
+`/homeassistant/.lovelace-backups/dashboard-unknown-power-monitor-20260829-204845.json`
+（改法：WS `lovelace/config/save`，参数 `url_path: dashboard-unknown` +
+`config`；勿直改 `.storage/`）。验证：WS 读回 18 实体 diff ✓、gauge
+配置一致 ✓、URL `http://hass.windy.lan:8123/dashboard-unknown/power-monitor`。
+
+> **Seasonal gauge switch (W1N-240 已知事项):** 每年 **11-01** 把
+> `power-monitor` 视图「本月累计」gauge 切到冬季 `max:450` /
+> `0/200/400`，**5-01** 切回夏季 `max:650` / `0/260/600`（与模板
+> `now().month` 季节逻辑对齐；模板常量在 Block B/D `variables`）。
+
 Home PPPoE IPv4 to CSG is still blackholed (`curl -4` to `218.19.148.218:443`
 times out). `end0` IPv6 is enabled (`ipv6.method: auto`); from HA,
 `curl -6 https://95598.csg.cn` returns HTTP 200 via `240e:f9:8060::1:16`.
diff --git a/runbooks/home-assistant-maintenance.md b/runbooks/home-assistant-maintenance.md
index 97e8015..a887909 100644
--- a/runbooks/home-assistant-maintenance.md
+++ b/runbooks/home-assistant-maintenance.md
@@ -284,8 +284,10 @@ print(urllib.request.urlopen(req, timeout=60).status)
 
 7. **Do not edit the dashboard or `templates/csg_sensors.yaml` for an
    install.** Entity IDs did not change across v1.3.0/v1.3.1/v1.3.2.
-   Template `| float(0)` turns native `unavailable` into fake zeros; that
-   is a follow-up, not part of the zip install.
+   (The old `| float(0)` fake-zero follow-up was resolved 2026-08-29 by
+   W1N-239: template sensors now carry `availability` templates and show
+   `unavailable` instead of fake zeros when native CSG sensors are down.
+   Template edits go through that issue, not the install path.)
 
 #### Verify (CSG, after v1.3.2 / W1N-118)