diff --git a/include/fmt/time.h b/include/fmt/time.h
index 6dc45abf9cb99..f26728700dd56 100644
--- a/include/fmt/time.h
+++ b/include/fmt/time.h
@@ -51,7 +51,7 @@ inline std::tm localtime(std::time_t time) {
 
     bool fallback(int res) { return res == 0; }
 
-#ifndef _MSC_VER
+#if !FMT_MSC_VER
     bool fallback(internal::null<>) {
       using namespace fmt::internal;
       std::tm *tm = std::localtime(&time_);
@@ -90,7 +90,7 @@ inline std::tm gmtime(std::time_t time) {
 
     bool fallback(int res) { return res == 0; }
 
-#ifndef _MSC_VER
+#if !FMT_MSC_VER
     bool fallback(internal::null<>) {
       std::tm *tm = std::gmtime(&time_);
       if (tm) tm_ = *tm;