diff --git a/py/hexagram/cluster.py b/py/hexagram/cluster.py
index 8257486..42ee02c 100644
--- a/py/hexagram/cluster.py
+++ b/py/hexagram/cluster.py
@@ -90,6 +90,8 @@ class AmbientTemp(TextGauge):
     def __init__(self, x: float, y: float, align: Align):
         super().__init__(x, y, -100, 100, align)
 
+        self.value = 0
+
     def format_text(self):
         return "%.1f°C" % self.value