diff --git a/routers/web/repo/activity.go b/routers/web/repo/activity.go
index 7f2ed8cb26..a1f1106159 100644
--- a/routers/web/repo/activity.go
+++ b/routers/web/repo/activity.go
@@ -47,8 +47,8 @@ func Activity(ctx *context.Context) {
 		ctx.Data["Period"] = "weekly"
 		timeFrom = timeUntil.Add(-time.Hour * 168)
 	}
-	ctx.Data["DateFrom"] = timeFrom.Format("January 2, 2006")
-	ctx.Data["DateUntil"] = timeUntil.Format("January 2, 2006")
+	ctx.Data["DateFrom"] = timeFrom.Format("2006-01-02")
+	ctx.Data["DateUntil"] = timeUntil.Format("2006-01-02")
 	ctx.Data["PeriodText"] = ctx.Tr("repo.activity.period." + ctx.Data["Period"].(string))
 
 	var err error