diff --git a/src/document/migrate-scene-document.ts b/src/document/migrate-scene-document.ts
index e14ad8d5..33330a48 100644
--- a/src/document/migrate-scene-document.ts
+++ b/src/document/migrate-scene-document.ts
@@ -191,6 +191,7 @@ import {
   SCENE_TRANSITION_ENTITIES_SCENE_DOCUMENT_VERSION,
   SCENE_TRANSITION_SEQUENCE_EFFECTS_SCENE_DOCUMENT_VERSION,
   SCHEDULER_CONTROL_EFFECTS_SCENE_DOCUMENT_VERSION,
+  SHADER_SKY_SCENE_DOCUMENT_VERSION,
   SPATIAL_AUDIO_SCENE_DOCUMENT_VERSION,
   STARTER_PBR_MATERIAL_LIBRARY_SCENE_DOCUMENT_VERSION,
   PROJECT_NAME_SCENE_DOCUMENT_VERSION,
@@ -5153,6 +5154,8 @@ export function migrateSceneDocument(source: unknown): SceneDocument {
     source.version !== DAWN_DUSK_BACKGROUND_IMAGE_SCENE_DOCUMENT_VERSION &&
     source.version !== WHITEBOX_BOX_LIGHT_VOLUME_SCENE_DOCUMENT_VERSION &&
     source.version !== CELESTIAL_BODY_OVERLAY_SCENE_DOCUMENT_VERSION &&
+    source.version !== SHADER_SKY_SCENE_DOCUMENT_VERSION &&
+    source.version !== SCENE_DOCUMENT_VERSION &&
     source.version !== FOLLOW_ACTOR_PATH_SMOOTH_SCENE_DOCUMENT_VERSION
   ) {
     throw new Error(
diff --git a/src/document/scene-document-validation.ts b/src/document/scene-document-validation.ts
index 84424374..698e12e2 100644
--- a/src/document/scene-document-validation.ts
+++ b/src/document/scene-document-validation.ts
@@ -352,12 +352,12 @@ function validateWorldShaderSkySettings(
     );
   }
 
-  if (!isFiniteNumberInRange(settings.horizonHeight, -1, 1)) {
+  if (!isFiniteNumberInRange(settings.horizonHeight, -0.5, 0.5)) {
     diagnostics.push(
       createDiagnostic(
         "error",
         "invalid-world-shader-sky-horizon-height",
-        "World shader sky horizon height must stay between -1 and 1.",
+        "World shader sky horizon height must stay between -0.5 and 0.5.",
         `${path}.horizonHeight`
       )
     );
diff --git a/src/document/scene-document.ts b/src/document/scene-document.ts
index da8addba..319384b3 100644
--- a/src/document/scene-document.ts
+++ b/src/document/scene-document.ts
@@ -29,7 +29,8 @@ import {
 } from "../sequencer/project-sequences";
 import type { Terrain } from "./terrains";
 
-export const SCENE_DOCUMENT_VERSION = 71 as const;
+export const SCENE_DOCUMENT_VERSION = 72 as const;
+export const SHADER_SKY_HORIZON_HEIGHT_SCENE_DOCUMENT_VERSION = 72 as const;
 export const SHADER_SKY_SCENE_DOCUMENT_VERSION = 71 as const;
 export const CELESTIAL_BODY_OVERLAY_SCENE_DOCUMENT_VERSION = 70 as const;
 export const WHITEBOX_BOX_LIGHT_VOLUME_SCENE_DOCUMENT_VERSION = 69 as const;
diff --git a/src/rendering/world-background-renderer.ts b/src/rendering/world-background-renderer.ts
index 0f73a9d1..82b93982 100644
--- a/src/rendering/world-background-renderer.ts
+++ b/src/rendering/world-background-renderer.ts
@@ -875,6 +875,7 @@ export class WorldBackgroundRenderer {
 
   private syncShaderSkyState(state: WorldShaderSkyRenderState | null) {
     if (state === null) {
+      this.shaderSkyMaterial.uniforms.uHorizonHeight.value = 0;
       this.shaderSkyMaterial.uniforms.uStarVisibility.value = 0;
       this.shaderSkyMaterial.uniforms.uSunVisible.value = 0;
       this.shaderSkyMaterial.uniforms.uMoonVisible.value = 0;