diff --git a/src/index.js b/src/index.js
index 7005f63caa5b3965e6d7d16b807162b2722a397e..2d89fc0a8b49aafafd4ec16cbdf35fb7dc6a4814 100644
--- a/src/index.js
+++ b/src/index.js
@@ -144,9 +144,13 @@ function getMomentFormat(timeRange, startDate, enedisValueOrder) {
     case 'urlCdcJour':
       return moment(startDate, 'DD/MM/YYYY').add(enedisValueOrder, 'day')
     case 'urlCdcMois':
-      return moment(startDate, 'DD/MM/YYYY').add(enedisValueOrder, 'month')
+      return moment(startDate, 'DD/MM/YYYY')
+        .startOf('month')
+        .add(enedisValueOrder, 'month')
     case 'urlCdcAn':
-      return moment(startDate, 'DD/MM/YYYY').add(enedisValueOrder, 'year')
+      return moment(startDate, 'DD/MM/YYYY')
+        .startOf('year')
+        .add(enedisValueOrder, 'year')
     default:
       throw new Error('unknown timeRange ' + timeRange)
   }