diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
index 75408a5..a305f60 100644
--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -12,7 +12,7 @@
 # input used in their production; they are not affected by this license.
 
 include (${TOP}/cmake/version.cmake)
-string(TIMESTAMP DATE "%d-%m-%Y")
+string(TIMESTAMP DATE "%d-%m-%Y" UTC)
 string(TIMESTAMP YEAR "%Y")
 
 find_package(PythonInterp REQUIRED)