diff --git a/app/routers/stats.py b/app/routers/stats.py
index 601e66c..76ab501 100644
--- a/app/routers/stats.py
+++ b/app/routers/stats.py
@@ -39,9 +39,11 @@ async def get_plant_stats(
         today = datetime.now().date()
         today_str = today.isoformat()
         
+        # 1. 과거 데이터 조회 (daily_stats)
         # 1. 과거 데이터 조회 (daily_stats)
         if period == "day":
-            start_date = today - timedelta(days=30)
+            # 이번 달 1일부터 오늘까지
+            start_date = today.replace(day=1)
             date_filter = start_date.isoformat()
         elif period == "month":
             start_date = today.replace(day=1) - timedelta(days=365)