diff --git a/src/analysis/stat.py b/src/analysis/stat.py
index a20b753b791cbd5a1c00d6cb1149f7e098d1cf2c..0dd73976809a8888d35328f51e84f22b690db639 100644
--- a/src/analysis/stat.py
+++ b/src/analysis/stat.py
@@ -184,6 +184,6 @@ def detect_lines(df: pd.DataFrame, st: pd.DataFrame) -> None:
         maxBytes=2**17,
     )
 
-    outfile = NamedTemporaryFile(delete=False)
+    outfile = NamedTemporaryFile(delete=False, suffix=".html")
     outfile.write(html.encode("utf-8"))
     webbrowser.open(outfile.name)
diff --git a/src/analysis/trajectories_map.py b/src/analysis/trajectories_map.py
index 3130947dc2647f22ea5142b323e9bb5dde29cfa2..6706c75161ba25b6fbb4137c49e12c309a97b1b8 100644
--- a/src/analysis/trajectories_map.py
+++ b/src/analysis/trajectories_map.py
@@ -362,7 +362,7 @@ def build_map(st: pd.DataFrame, df: pd.DataFrame) -> None:
     m.get_root().add_child(macro)
 
     # Save the map to a temporary file and open it with a web browser
-    outfile = NamedTemporaryFile(delete=False)
+    outfile = NamedTemporaryFile(delete=False, suffix=".html")
     m.save(outfile.file)
 
     webbrowser.open(outfile.name)