@@ -0,0 +1,27 @@
+from django.template import Library
+
+register = Library()
+
+
+@register.filter
+def min(object_list, field):
+    """
+    Returns the min value given an object_list and a field.
+
+    Example:
+        {{ forecast|min:"high_temp" }}
+    """
+    value_list = [getattr(o, obj, None) for o in object_list]
+    return min(value_list)
+
+
+@register.filter
+def max(object_list, field):
+    """
+    Returns the max value given an object_list and a field.
+
+    Example:
+        {{ forecast|max:"high_temp" }}
+    """
+    value_list = [getattr(o, obj, None) for o in object_list]
+    return max(value_list)