diff --git a/compose.yaml b/compose.yaml
index a9bde46..d9b5242 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -9,6 +9,7 @@ services:
       - path: .env
         required: false
     environment:
+      TZ: ${TZ:-Asia/Shanghai}
       DATABASE_URL: ${DATABASE_URL:-sqlite:////app/data/checkin.db}
       LOG_FILE: ${LOG_FILE:-/app/logs/backend.log}
       SESSION_DIR: ${SESSION_DIR:-/app/sessions}
@@ -40,6 +41,8 @@ services:
         condition: service_healthy
     ports:
       - "${CHECKIN_WEB_PORT:-3090}:80"
+    environment:
+      TZ: ${TZ:-Asia/Shanghai}
     restart: unless-stopped
     healthcheck:
       test: ["CMD-SHELL", "wget -qO- http://127.0.0.1/health >/dev/null"]
diff --git a/deploy/compose.env.example b/deploy/compose.env.example
index 309afaa..a3f3c04 100644
--- a/deploy/compose.env.example
+++ b/deploy/compose.env.example
@@ -4,6 +4,9 @@
 # Public web port exposed by the web service.
 CHECKIN_WEB_PORT=3090
 
+# Container timezone. Asia/Shanghai is UTC+8.
+TZ=Asia/Shanghai
+
 # ==================== Backend runtime paths ====================
 # Container-local defaults for the Compose deployment.
 DATABASE_URL=sqlite:////app/data/checkin.db