diff --git a/integrations/server/test_covidcast.py b/integrations/server/test_covidcast.py
index 4963ca9a8..8b7fc6f52 100644
--- a/integrations/server/test_covidcast.py
+++ b/integrations/server/test_covidcast.py
@@ -81,6 +81,18 @@ def _insert_placeholder_set_five(self):
     self._insert_rows(rows)
     return rows 
 
+  def _insert_placeholder_set_with_weeks(self):
+    rows = [
+      CovidcastTestRow.make_default_row(
+        time_value=2021_05+i, time_type="week",
+        source="nchs-mortality", signal="deaths_covid_incidence_num",
+        geo_type="state", geo_value="il",
+        value=i*i)
+      for i in [0, 1, 2]
+    ]
+    self._insert_rows(rows)
+    return rows
+
   def test_round_trip(self):
     """Make a simple round-trip with some sample data."""
 
@@ -445,3 +457,22 @@ def test_date_formats(self):
 
     # assert that the right data came back
     self.assertEqual(len(response['epidata']), 2 * 3)
+
+
+  def test_week_formats(self):
+    """Test different ways to specify week ranges are accepted."""
+
+    rows = self._insert_placeholder_set_with_weeks()
+    expected = {
+      'result': 1,
+      'epidata': [r.as_api_row_dict() for r in rows],
+      'message': 'success',
+    }
+
+    colond = self.request_based_on_row(rows[0], time_values="202105:202107")
+    dashed = self.request_based_on_row(rows[0], time_values="202105-202107")
+    enumed = self.request_based_on_row(rows[0], time_values="202105,202106,202107")
+
+    self.assertEqual(expected, colond)
+    self.assertEqual(expected, dashed)
+    self.assertEqual(expected, enumed)
diff --git a/src/server/_params.py b/src/server/_params.py
index 5eeb85ec4..d565f894d 100644
--- a/src/server/_params.py
+++ b/src/server/_params.py
@@ -439,7 +439,18 @@ def extract_dates(key: Union[str, Sequence[str]]) -> Optional[TimeValues]:
             values.append(r)
             continue
         # parse other date formats
-        r = parse_day_value(part)
+        dashless_part = part.replace("-", "")
+        if len(dashless_part) in (6, 12):
+            # if there are 6 or 12 (hopefully integer) chars in this, it
+            # should be a week or week range (YYYYWW or YYYYWWYYYYWW)
+            r = parse_week_value(part)
+        elif len(dashless_part) in (8, 16):
+            # if its 8 or 16, it should be a day or
+            # day range (YYYYMMDD or YYYYMMDDYYYYMMDD)
+            r = parse_day_value(part)
+        else:
+            # other time types tbd lol
+            raise ValidationFailedException(f"unrecognized date format: {part}")
         values.append(r)
     return values