diff --git a/src/env_dispatch.cpp b/src/env_dispatch.cpp
index c45034a86..c472ae2ad 100644
--- a/src/env_dispatch.cpp
+++ b/src/env_dispatch.cpp
@@ -38,6 +38,7 @@
 #include "env_universal_common.h"
 #include "event.h"
 #include "fallback.h"  // IWYU pragma: keep
+#include "flog.h"
 #include "function.h"
 #include "global_safety.h"
 #include "history.h"
@@ -498,22 +499,22 @@ static void init_locale(const environment_t &vars) {
         const auto var = vars.get(var_name, ENV_EXPORT);
         const std::string &name = wcs2string(var_name);
         if (var.missing_or_empty()) {
-            debug(5, L"locale var %s missing or empty", name.c_str());
+            FLOGF(env_locale, L"locale var %s missing or empty", name.c_str());
             unsetenv_lock(name.c_str());
         } else {
             const std::string value = wcs2string(var->as_string());
-            debug(5, L"locale var %s='%s'", name.c_str(), value.c_str());
+            FLOGF(env_locale, L"locale var %s='%s'", name.c_str(), value.c_str());
             setenv_lock(name.c_str(), value.c_str(), 1);
         }
     }
 
     char *locale = setlocale(LC_ALL, "");
     fish_setlocale();
-    debug(5, L"init_locale() setlocale(): '%s'", locale);
+    FLOGF(env_locale, L"init_locale() setlocale(): '%s'", locale);
 
     const char *new_msg_locale = setlocale(LC_MESSAGES, NULL);
-    debug(5, L"old LC_MESSAGES locale: '%s'", old_msg_locale);
-    debug(5, L"new LC_MESSAGES locale: '%s'", new_msg_locale);
+    FLOGF(env_locale, L"old LC_MESSAGES locale: '%s'", old_msg_locale);
+    FLOGF(env_locale, L"new LC_MESSAGES locale: '%s'", new_msg_locale);
 #ifdef HAVE__NL_MSG_CAT_CNTR
     if (std::strcmp(old_msg_locale, new_msg_locale)) {
         // Make change known to GNU gettext.
diff --git a/src/flog.h b/src/flog.h
index 4c0d9ad21..48b5728ba 100644
--- a/src/flog.h
+++ b/src/flog.h
@@ -58,6 +58,8 @@ class category_list_t {
     category_t proc_job_run{L"proc-job-run", L"Jobs getting started or continued"};
 
     category_t proc_termowner{L"proc-termowner", L"Terminal ownership events"};
+
+    category_t env_locale{L"env-locale", L"Changes to locale variables"};
 };
 
 /// The class responsible for logging.