diff --git a/s3tests_boto3/functional/test_s3.py b/s3tests_boto3/functional/test_s3.py
index 05fdb9c..5270a41 100644
--- a/s3tests_boto3/functional/test_s3.py
+++ b/s3tests_boto3/functional/test_s3.py
@@ -9659,7 +9659,7 @@ def test_lifecycle_expiration_header_put():
     bucket_name = get_new_bucket()
     client = get_client()
 
-    now = datetime.datetime.now(None)
+    now = datetime.datetime.utcnow()
     response = setup_lifecycle_expiration(
         client, bucket_name, 'rule1', 1, 'days1/')
     eq(check_lifecycle_expiration_header(response, now, 'rule1', 1), True)
@@ -9673,7 +9673,7 @@ def test_lifecycle_expiration_header_head():
     bucket_name = get_new_bucket()
     client = get_client()
 
-    now = datetime.datetime.now(None)
+    now = datetime.datetime.utcnow()
     response = setup_lifecycle_expiration(
         client, bucket_name, 'rule1', 1, 'days1/')