diff --git a/workflows/f/weather/weather_sync.schedule.yaml b/workflows/f/weather/weather_sync.schedule.yaml
new file mode 100644
index 0000000..ff6a30c
--- /dev/null
+++ b/workflows/f/weather/weather_sync.schedule.yaml
@@ -0,0 +1,10 @@
+args: {}
+cron_version: v2
+email: akiracraftwork@gmail.com
+enabled: true
+is_flow: true
+no_flow_overlap: false
+schedule: 0 0 6 * * *
+script_path: f/weather/weather_sync
+timezone: Asia/Tokyo
+ws_error_handler_muted: false
diff --git a/workflows/f/weather/weather_sync__flow/flow.yaml b/workflows/f/weather/weather_sync__flow/flow.yaml
new file mode 100644
index 0000000..4d4eaa8
--- /dev/null
+++ b/workflows/f/weather/weather_sync__flow/flow.yaml
@@ -0,0 +1,18 @@
+summary: Weather Sync - 気象データ日次同期
+description: Open-Meteo から昨日の気象データを取得し、Keinasystem DB に保存する。毎朝6時実行。
+value:
+  modules:
+    - id: a
+      summary: 気象データ取得・同期
+      value:
+        type: rawscript
+        content: '!inline 気象データ取得・同期.py'
+        input_transforms: {}
+        lock: '!inline 気象データ取得・同期.lock'
+        language: python3
+schema:
+  $schema: 'https://json-schema.org/draft/2020-12/schema'
+  type: object
+  order: []
+  properties: {}
+  required: []
diff --git a/workflows/f/weather/weather_sync__flow/気象データ取得・同期.lock b/workflows/f/weather/weather_sync__flow/気象データ取得・同期.lock
new file mode 100644
index 0000000..78d89bd
--- /dev/null
+++ b/workflows/f/weather/weather_sync__flow/気象データ取得・同期.lock
@@ -0,0 +1,12 @@
+# py: 3.12
+anyio==4.12.1
+certifi==2026.2.25
+charset-normalizer==3.4.4
+h11==0.16.0
+httpcore==1.0.9
+httpx==0.28.1
+idna==3.11
+requests==2.32.5
+typing-extensions==4.15.0
+urllib3==2.6.3
+wmill==1.646.0
\ No newline at end of file
diff --git a/workflows/f/weather/weather_sync__flow/気象データ取得・同期.py b/workflows/f/weather/weather_sync__flow/気象データ取得・同期.py
new file mode 100644
index 0000000..9b322e5
--- /dev/null
+++ b/workflows/f/weather/weather_sync__flow/気象データ取得・同期.py
@@ -0,0 +1,72 @@
+import wmill
+import requests
+import datetime
+
+LATITUDE  = 33.213
+LONGITUDE = 133.133
+TIMEZONE  = "Asia/Tokyo"
+
+OPEN_METEO_URL = "https://archive-api.open-meteo.com/v1/archive"
+DAILY_VARS = [
+    "temperature_2m_mean",
+    "temperature_2m_max",
+    "temperature_2m_min",
+    "sunshine_duration",
+    "precipitation_sum",
+    "wind_speed_10m_max",
+    "surface_pressure_min",
+]
+
+
+def main():
+    api_key  = wmill.get_variable("u/admin/KEINASYSTEM_API_KEY")
+    base_url = wmill.get_variable("u/admin/KEINASYSTEM_API_URL").rstrip("/")
+    sync_url = f"{base_url}/api/weather/sync/"
+
+    yesterday = (datetime.date.today() - datetime.timedelta(days=1)).isoformat()
+    print(f"Fetching weather data for {yesterday} ...")
+
+    params = {
+        "latitude":   LATITUDE,
+        "longitude":  LONGITUDE,
+        "start_date": yesterday,
+        "end_date":   yesterday,
+        "daily":      DAILY_VARS,
+        "timezone":   TIMEZONE,
+    }
+    resp = requests.get(OPEN_METEO_URL, params=params, timeout=30)
+    if resp.status_code != 200:
+        raise Exception(f"Open-Meteo API error: {resp.status_code} {resp.text[:300]}")
+
+    daily = resp.json().get("daily", {})
+    dates = daily.get("time", [])
+    if not dates:
+        print("No data returned from Open-Meteo.")
+        return {"status": "no_data"}
+
+    sunshine_raw = daily.get("sunshine_duration", [])
+    records = []
+    for i, d in enumerate(dates):
+        sun_sec = sunshine_raw[i]
+        records.append({
+            "date":         d,
+            "temp_mean":    daily["temperature_2m_mean"][i],
+            "temp_max":     daily["temperature_2m_max"][i],
+            "temp_min":     daily["temperature_2m_min"][i],
+            "sunshine_h":   round(sun_sec / 3600, 2) if sun_sec is not None else None,
+            "precip_mm":    daily["precipitation_sum"][i],
+            "wind_max":     daily["wind_speed_10m_max"][i],
+            "pressure_min": daily["surface_pressure_min"][i],
+        })
+
+    headers = {
+        "X-API-Key":     api_key,
+        "Content-Type":  "application/json",
+    }
+    post_resp = requests.post(sync_url, json=records, headers=headers, timeout=30)
+    if post_resp.status_code not in (200, 201):
+        raise Exception(f"Keinasystem sync error: {post_resp.status_code} {post_resp.text[:300]}")
+
+    result = post_resp.json()
+    print(f"Sync complete: {result}")
+    return result
diff --git a/workflows/wmill-lock.yaml b/workflows/wmill-lock.yaml
index a4ca909..518e086 100644
--- a/workflows/wmill-lock.yaml
+++ b/workflows/wmill-lock.yaml
@@ -9,6 +9,8 @@ locks:
   f/mail/mail_filter__flow+メール取得・判定・通知.py: 0b9cc3ff72d6f3445d46005a657903ae8f195104d1623b47079d13691811c602
   f/shiraou/shiraou_notification__flow+__flow_hash: 94825ff4362b6e4b6d165f8e17a51ebf8e5ef4da3e0ec1407a94b614ecab19dd
   f/shiraou/shiraou_notification__flow+変更確認・line通知.py: ac80896991cce8132cfbf34d5dae20d3c09de5bc74a55c500e4c8705dd6a9d88
+  f/weather/weather_sync__flow+__flow_hash: 8af44676b2a175c1cc105028682f18e4bfbf7bf9de2722263a7d85c13c825f08
+  f/weather/weather_sync__flow+気象データ取得・同期.py: 86c9953ec7346601eaa13c681e2db5c01c9a5b4b45a3c47e8667ad3c47557029
   g/all/setup_app__app+__app_hash: d71add32e14e552d1a4c861c972a50d9598b07c0af201bbadec5b59bbd99d7e3
   g/all/setup_app__app+change_account.deno.ts: 3c592cac27e9cdab0de6ae19270bcb08c7fa54355ad05253a12de2351894346b
   u/admin/hub_sync: aaf9fd803fa229f3029d1bb02bbe3cc422fce680cad39c4eec8dd1da115de102