diff --git a/larigira/tests/test_time_every.py b/larigira/tests/test_time_every.py
index ae621c2..dfbdf70 100644
--- a/larigira/tests/test_time_every.py
+++ b/larigira/tests/test_time_every.py
@@ -61,6 +61,14 @@ def tenseconds(now, request):
         'end': now + days(1)})
 
 
+@pytest.fixture(params=[1, 2, 3, 4, 5, 6, 7, 8])
+def manyweeks(request):
+    yield FrequencyAlarm({
+        'interval': '{}w'.format(request.param),
+        'start': 0
+    })
+
+
 def days(n):
     return timedelta(days=n)
 
@@ -155,6 +163,15 @@ def test_sunday_is_not_0():
     assert 'Not a valid weekday:' in excinfo.value.args[0]
 
 
+def test_long_interval(manyweeks):
+    t = datetime.fromtimestamp(1)
+    expected = manyweeks.interval
+    got = manyweeks.next_ring(t)
+    assert got is not None
+    assert int(got.strftime('%s')) == expected
+    assert manyweeks.next_ring(got) is not None
+
+
 def test_single_registered():
     timegenerate({
         'kind': 'single',
diff --git a/larigira/timegen_every.py b/larigira/timegen_every.py
index 126180c..bd4f5dd 100644
--- a/larigira/timegen_every.py
+++ b/larigira/timegen_every.py
@@ -100,7 +100,7 @@ class FrequencyAlarm(Alarm):
         # fact, it is necessary to retry until a valid event/weekday is
         # found. a "while True" might have been more elegant (and maybe
         # fast), but this gives a clear upper bound to the cycle.
-        for _ in range(60*60*24*7 // self.interval):
+        for _ in range(max(60*60*24*7 // self.interval, 1)):
             n_interval = (
                 (current_time - self.start).total_seconds() // self.interval
                 ) + 1