diff --git a/recipe/meta.json b/recipe/meta.json
index 8a55437b5..767c182c6 100644
--- a/recipe/meta.json
+++ b/recipe/meta.json
@@ -36,5 +36,5 @@
       "requests >=2.32,<2.33"
     ]
   },
-  "version": "2.12.1"
+  "version": "2.12.2"
 }
diff --git a/src/uwtools/config/support.py b/src/uwtools/config/support.py
index 8947d13d5..9ca6b02f2 100644
--- a/src/uwtools/config/support.py
+++ b/src/uwtools/config/support.py
@@ -51,6 +51,16 @@ def add_yaml_representers() -> None:
     """
     Add representers to the YAML dumper for custom types.
     """
+
+    def timedelta2str(dumper: yaml.dumper.Dumper, data: timedelta) -> yaml.ScalarNode:
+        seconds = int(data.total_seconds())
+        hours = seconds // 3600
+        seconds %= 3600
+        minutes = seconds // 60
+        seconds %= 60
+        s = f"{hours}:{minutes:02d}:{seconds:02d}"
+        return dumper.represent_scalar("!timedelta", s)
+
     yaml.add_representer(Namelist, _represent_namelist)
     yaml.add_representer(OrderedDict, _represent_ordereddict)
     yaml.add_representer(
@@ -59,10 +69,7 @@ def add_yaml_representers() -> None:
             "tag:yaml.org,2002:timestamp", to_iso8601(data)
         ),
     )
-    yaml.add_representer(
-        timedelta,
-        lambda dumper, data: dumper.represent_scalar("!timedelta", str(data)),
-    )
+    yaml.add_representer(timedelta, timedelta2str)
     for tag_class in [UWYAMLConvert, UWYAMLGlob, UWYAMLRemove]:
         yaml.add_representer(tag_class, tag_class.represent)
 
diff --git a/src/uwtools/resources/info.json b/src/uwtools/resources/info.json
index d231de7c8..d82b3afce 100644
--- a/src/uwtools/resources/info.json
+++ b/src/uwtools/resources/info.json
@@ -1,4 +1,4 @@
 {
   "buildnum": "0",
-  "version": "2.12.1"
+  "version": "2.12.2"
 }
diff --git a/src/uwtools/tests/config/test_support.py b/src/uwtools/tests/config/test_support.py
index 657db569d..5d903caf1 100644
--- a/src/uwtools/tests/config/test_support.py
+++ b/src/uwtools/tests/config/test_support.py
@@ -4,6 +4,7 @@
 
 from collections import OrderedDict
 from datetime import datetime, timedelta
+from textwrap import dedent
 
 import f90nml  # type: ignore[import-untyped]
 import yaml
@@ -54,6 +55,22 @@ def test_config_support_add_yaml_representers__represent_ordereddict():
     assert yaml.dump(ordereddict_values, default_flow_style=True).strip() == expected
 
 
+def test_config_support_add_yaml_representers__represent_timedelta(tmp_path):
+    support.add_yaml_representers()
+    s = """
+    start: !datetime 2025-01-01T00
+    stop: !datetime 2025-01-03T03
+    raw: !timedelta '{{ ((stop - start) * 0.8).total_seconds() / 3600 }}'
+    """
+    path = tmp_path / "config.yaml"
+    path.write_text(dedent(s))
+    config = YAMLConfig(config=path)
+    config.dereference()
+    assert config["raw"] == timedelta(days=1, seconds=60480)
+    config.dump(path)
+    assert path.read_text().strip().split("\n")[-1] == "raw: !timedelta '40:48:00'"
+
+
 @mark.parametrize(
     ("d", "n"), [({1: 42}, 1), ({1: {2: 42}}, 2), ({1: {2: {3: 42}}}, 3), ({1: {}}, 2)]
 )
@@ -182,6 +199,17 @@ def test_UWYAMLConvert_list_ok(self, loader):
         assert ts.converted == [1, 2, 3]
         self.comp(ts, "!list '[1,2,3,]'")
 
+    def test_UWYAMLConvert__timedelta_no(self, loader):
+        ts = support.UWYAMLConvert(loader, yaml.ScalarNode(tag="!timedelta", value="null"))
+        with raises(ValueError, match="could not convert string to float"):
+            assert ts.converted
+
+    @mark.parametrize("value", ["49", "49:00", "49:00:00"])
+    def test_UWYAMLConvert__timedelta_ok(self, loader, value):
+        ts = support.UWYAMLConvert(loader, yaml.ScalarNode(tag="!timedelta", value=value))
+        assert ts.converted == timedelta(hours=49)
+        self.comp(ts, f"!timedelta '{value}'")
+
     def test_UWYAMLConvert_tagged_string(self, loader):
         ts = support.UWYAMLConvert(loader, yaml.ScalarNode(tag="!list", value="{{ foo }}"))
         assert ts.tagged_string == "!list '{{ foo }}'"