diff --git a/covjsonkit/encoder/VerticalProfile.py b/covjsonkit/encoder/VerticalProfile.py
index 0282107..0781f89 100644
--- a/covjsonkit/encoder/VerticalProfile.py
+++ b/covjsonkit/encoder/VerticalProfile.py
@@ -229,7 +229,7 @@ def from_polytope(self, result, date_key: str = "date") -> dict:
                         mm = mars_metadata.copy()
                         mm["number"] = num
                         mm["Forecast date"] = date
-                        mm["step"] = step
+                        mm["step"] = normalize_step_value(step)
                         # del mm["step"]
                         self.add_coverage(mm, coordinates[date][i][s], val_dict[step])
 
diff --git a/covjsonkit/version.py b/covjsonkit/version.py
index 198d6db..f289274 100644
--- a/covjsonkit/version.py
+++ b/covjsonkit/version.py
@@ -1 +1 @@
-__version__ = "0.2.20"
+__version__ = "0.2.21"
diff --git a/pyproject.toml b/pyproject.toml
index c67d159..a1e954a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ markers = ["data: uses test data (deselect with '-m \"not data\"')",]
 
 [project]
 name = "covjsonkit"
-version = "0.2.20"
+version = "0.2.21"
 dependencies = [
     "pandas<3",
     "orjson",