diff --git a/include/fmt/chrono.h b/include/fmt/chrono.h
index 8bd16805..4b1804da 100644
--- a/include/fmt/chrono.h
+++ b/include/fmt/chrono.h
@@ -894,13 +894,13 @@ struct chrono_formatter {
   void write_pinf() { std::copy_n("inf", 3, out); }
   void write_ninf() { std::copy_n("-inf", 4, out); }
 
-  void format_localized(const tm& time, const char* format) {
+  void format_localized(const tm& time, char format, char modifier = 0) {
     if (isnan(val)) return write_nan();
     auto locale = context.locale().template get<std::locale>();
     auto& facet = std::use_facet<std::time_put<char_type>>(locale);
     std::basic_ostringstream<char_type> os;
     os.imbue(locale);
-    facet.put(os, os, ' ', &time, format, format + std::char_traits<char_type>::length(format));
+    facet.put(os, os, ' ', &time, format, modifier);
     auto str = os.str();
     std::copy(str.begin(), str.end(), out);
   }
@@ -930,8 +930,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(hour(), 2);
     auto time = tm();
     time.tm_hour = to_nonnegative_int(hour(), 24);
-    const char_type format[] { '%', 'O', 'H', 0 };
-    format_localized(time, format);
+    format_localized(time,  'H', 'O');
   }
 
   void on_12_hour(numeric_system ns) {
@@ -940,8 +939,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(hour12(), 2);
     auto time = tm();
     time.tm_hour = to_nonnegative_int(hour12(), 12);
-    const char_type format[] { '%', 'O', 'I', 0 };
-    format_localized(time, format);
+    format_localized(time, 'I', 'O');
   }
 
   void on_minute(numeric_system ns) {
@@ -950,8 +948,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(minute(), 2);
     auto time = tm();
     time.tm_min = to_nonnegative_int(minute(), 60);
-    const char_type format[] { '%', 'O', 'M', 0 };
-    format_localized(time, format);
+    format_localized(time, 'M', 'O');
   }
 
   void on_second(numeric_system ns) {
@@ -976,14 +973,12 @@ struct chrono_formatter {
     }
     auto time = tm();
     time.tm_sec = to_nonnegative_int(second(), 60);
-    const char_type format[] { '%', 'O', 'S', 0 };
-    format_localized(time, format);
+    format_localized(time, 'S', 'O');
   }
 
   void on_12_hour_time() {
     if (handle_nan_inf()) return;
-    const char_type format[] { '%', 'r', 0 };
-    format_localized(time(), format);
+    format_localized(time(), 'r');
   }
 
   void on_24_hour_time() {
@@ -1007,8 +1002,7 @@ struct chrono_formatter {
 
   void on_am_pm() {
     if (handle_nan_inf()) return;
-    const char_type format[] { '%', 'p', 0 };
-    format_localized(time(), format);
+    format_localized(time(), 'p');
   }
 
   void on_duration_value() {