diff --git a/agenda/__init__.py b/agenda/__init__.py
index 21a0a0e..217590d 100644
--- a/agenda/__init__.py
+++ b/agenda/__init__.py
@@ -313,13 +313,21 @@ def critical_mass(start_date: date, limit: int = 12) -> list[Event]:
     events: list[Event] = []
     current_date = start_date
 
+    tz = pytz.timezone("Europe/London")
+    t = time(18, 0)
+
     for _ in range(limit):
         # Calculate the last Friday of the current month
         last_friday = current_date + relativedelta(day=31, weekday=FR(-1))
 
         # Include it in the list only if it's on or after the start_date
         if last_friday >= start_date:
-            events.append(Event(name="critical_mass", date=last_friday))
+            events.append(
+                Event(
+                    name="critical_mass",
+                    date=tz.localize(datetime.combine(last_friday, t)),
+                )
+            )
 
         # Move to the next month
         current_date += relativedelta(months=1)