diff --git a/htmd/site.py b/htmd/site.py
index e6b655d..b562757 100644
--- a/htmd/site.py
+++ b/htmd/site.py
@@ -122,13 +122,13 @@ def truncate_post_html(post_html: str) -> str:
 MONTHS = {
     '01': 'January',
     '02': 'February',
-    '3': 'March',
-    '4': 'April',
-    '5': 'May',
-    '6': 'June',
-    '7': 'July',
-    '8': 'August',
-    '9': 'September',
+    '03': 'March',
+    '04': 'April',
+    '05': 'May',
+    '06': 'June',
+    '07': 'July',
+    '08': 'August',
+    '09': 'September',
     '10': 'October',
     '11': 'November',
     '12': 'December',
diff --git a/tests/test_post_dates.py b/tests/test_post_dates.py
index d2a43b6..8236659 100644
--- a/tests/test_post_dates.py
+++ b/tests/test_post_dates.py
@@ -414,3 +414,22 @@ def test_build_without_published() -> None:
             count += 1
 
     assert count == 1
+
+
+def test_build_with_post_in_each_month() -> None:
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        runner.invoke(start)
+        post_path = Path('posts') / 'example.md'
+        with post_path.open('r') as post_file:
+            lines = post_file.readlines()
+        for month in range(1, 13):
+            with post_path.open('w') as post_file:
+                for line in lines:
+                    if 'published' in line:
+                        post_file.write(f'published: 2014-{month:02}-03\n')
+                    else:
+                        post_file.write(line)
+
+            result = runner.invoke(build)
+            assert result.exit_code == 0