diff --git a/nix/build-all.py b/nix/build-all.py
index 5ea41c54d1..b0ab4e0a14 100644
--- a/nix/build-all.py
+++ b/nix/build-all.py
@@ -1380,7 +1380,8 @@ if "OpenCOLLADA" in targets:
 
 def python_consider_rc(python_version: str) -> str:
     # TODO: remove after Python 3.15 release.
-    if python_version == "3.15.0":
+    # Python 3.15.0 is released on 2026-10-01, before that only rc builds are available.
+    if python_version == "3.15.0" and date.today() < date(2026, 10, 2):
         python_version += "rc2"
     return python_version
 
diff --git a/win/installers.py b/win/installers.py
index 4dd40f5861..30531dbe55 100644
--- a/win/installers.py
+++ b/win/installers.py
@@ -21,6 +21,7 @@
 #                                                                             #
 ###############################################################################
 #
+import datetime
 import os
 import re
 import shutil
@@ -917,7 +918,8 @@ def install_qt6(
 
 def python_consider_rc(python_version: str) -> str:
     # TODO: remove after Python 3.15 release.
-    if python_version == "3.15.0":
+    # Python 3.15.0 is released on 2026-10-01, before that only rc builds are available.
+    if python_version == "3.15.0" and datetime.date.today() < datetime.date(2026, 10, 2):
         python_version += "-rc2"
     return python_version