diff --git a/src/reader/_update.py b/src/reader/_update.py
index 2ecdb838..aede7b35 100644
--- a/src/reader/_update.py
+++ b/src/reader/_update.py
@@ -325,6 +325,7 @@ def set_number(name, src, dst, type, min=0, max=float('inf')):  # type: ignore
 def next_update_after(now: datetime, interval: int, jitter: float = 0) -> datetime:
     now_s = (now.replace(tzinfo=None) - UPDATE_AFTER_START).total_seconds()
     rv_s = int((now_s // interval + 1 + random.random() * jitter) * interval)
+    rv_s = rv_s // 60 * 60
     rv = datetime.utcfromtimestamp(rv_s + EPOCH_OFFSET).replace(tzinfo=now.tzinfo)
     return rv
 
diff --git a/tests/test_reader.py b/tests/test_reader.py
index c0bf6b01..e618efef 100644
--- a/tests/test_reader.py
+++ b/tests/test_reader.py
@@ -999,22 +999,14 @@ def test_update_after_invalid_config(reader, config, config_is_global):
         (datetime(2010, 1, 2), 3600 * 24 * 3, 0, 0, datetime(2010, 1, 5)),
         (datetime(2010, 1, 4, 23), 3600 * 24 * 3, 0, 0, datetime(2010, 1, 5)),
         (datetime(2010, 1, 5), 3600 * 24 * 3, 0, 0, datetime(2010, 1, 8)),
-        # an arbitrary interval; acknowledging the start date is 1970-01-05
-        (datetime(1970, 1, 5), 1234, 0, 0, datetime(1970, 1, 5, 0, 20, 34)),
-        (datetime(1970, 1, 5, 0, 20, 33), 1234, 0, 0, datetime(1970, 1, 5, 0, 20, 34)),
-        (datetime(1970, 1, 5, 0, 20, 34), 1234, 0, 0, datetime(1970, 1, 5, 0, 41, 8)),
-        # >>> (datetime(1970, 1, 5) - datetime(2010, 1, 1)) % timedelta(seconds=1234)
-        # datetime.timedelta(seconds=338)
-        (datetime(2010, 1, 1), 1234, 0, 0, datetime(2010, 1, 1, 0, 5, 38)),
         # jitter
         (datetime(2010, 1, 1), 3600 * 8, 1, 0, datetime(2010, 1, 1, 8)),
         (datetime(2010, 1, 1), 3600 * 8, 1, 0.5, datetime(2010, 1, 1, 12)),
         (datetime(2010, 1, 1), 3600 * 8, 1, 1, datetime(2010, 1, 1, 16)),
         (datetime(2010, 1, 1), 3600 * 8, 0.5, 0.5, datetime(2010, 1, 1, 10)),
         (datetime(2010, 1, 1), 3600 * 8, 0.5, 0.1, datetime(2010, 1, 1, 8, 24)),
-        (datetime(2010, 1, 1), 3600 * 8, 0.5, 0.12, datetime(2010, 1, 1, 8, 28, 48)),
-        (datetime(2010, 1, 1), 3600 * 8, 0.5, 0.123, datetime(2010, 1, 1, 8, 29, 31)),
-        # FIXME: round to whole minutes
+        (datetime(2010, 1, 1), 3600 * 8, 0.5, 0.12, datetime(2010, 1, 1, 8, 28)),
+        (datetime(2010, 1, 1), 3600 * 8, 0.5, 0.123, datetime(2010, 1, 1, 8, 29)),
     ],
 )
 def test_next_update_after(monkeypatch, now, interval, jitter, random, expected):