diff --git a/pkgs/by-name/ni/nix-weather/package.nix b/pkgs/by-name/ni/nix-weather/package.nix
index 3f6aa492a66b..00f904a9144d 100644
--- a/pkgs/by-name/ni/nix-weather/package.nix
+++ b/pkgs/by-name/ni/nix-weather/package.nix
@@ -41,7 +41,7 @@ rustPlatform.buildRustPackage (finalAttrs: {
   ];
 
   # This is where `build.rs` puts manpages
-  MAN_OUT = "./man";
+  env.MAN_OUT = "./man";
 
   postInstall = ''
     cd crates/nix-weather