diff --git a/events/sexp_components.py b/events/sexp_components.py
index 0f45ef7..c14fad8 100644
--- a/events/sexp_components.py
+++ b/events/sexp_components.py
@@ -559,7 +559,8 @@ def _calendar_main_panel_html(ctx: dict) -> str:
 
             parts.append(f'<div class="{cell_cls}">')
             parts.append('<div class="flex justify-between items-center"><div class="flex flex-col">')
-            parts.append(f'<span class="sm:hidden text-[16px] text-stone-500">{day_date.strftime("%a")}</span>')
+            if day_date:
+                parts.append(f'<span class="sm:hidden text-[16px] text-stone-500">{day_date.strftime("%a")}</span>')
 
             # Clickable day number
             if day_date: