diff --git a/Source/cmCTest.cxx b/Source/cmCTest.cxx
index 364790b93..7f0702c83 100644
--- a/Source/cmCTest.cxx
+++ b/Source/cmCTest.cxx
@@ -74,8 +74,11 @@ struct tm* cmCTest::GetNightlyTime(std::string str,
   char buf[1024];
   // add todays year day and month to the time in str because
   // curl_getdate no longer assumes the day is today
-  sprintf(buf, "%d%02d%02d %s", lctime->tm_year+1900, lctime->tm_mday,
-          lctime->tm_mon, str.c_str());
+  sprintf(buf, "%d%02d%02d %s", 
+          lctime->tm_year+1900, 
+          lctime->tm_mon +1,
+          lctime->tm_mday,
+          str.c_str());
   cmCTestLog(this, OUTPUT, "Determine Nightly Start Time" << std::endl
     << "   Specified time: " << str.c_str() << std::endl);
   //Convert the nightly start time to seconds. Since we are