From d45a20af83e253a5d2943991480485deb389e5f5 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 29 Jan 2026 21:25:46 -0600
Subject: [PATCH] tweak

---
 esphome/components/time/real_time_clock.cpp | 27 ++++++++++++++-------
 esphome/components/time/real_time_clock.h   | 24 ++++++------------
 2 files changed, 26 insertions(+), 25 deletions(-)

diff --git a/esphome/components/time/real_time_clock.cpp b/esphome/components/time/real_time_clock.cpp
index 316600d2e4..e04bc3b3d5 100644
--- a/esphome/components/time/real_time_clock.cpp
+++ b/esphome/components/time/real_time_clock.cpp
@@ -25,7 +25,21 @@ RealTimeClock::RealTimeClock() = default;
 
 void RealTimeClock::dump_config() {
 #ifdef USE_TIME_TIMEZONE
-  ESP_LOGCONFIG(TAG, "Timezone: '%s'", this->timezone_.c_str());
+  int std_hours = -this->parsed_tz_.std_offset_seconds / 3600;
+  int std_mins = abs(this->parsed_tz_.std_offset_seconds % 3600) / 60;
+  if (std_mins == 0) {
+    ESP_LOGCONFIG(TAG, "Timezone: UTC%+d", std_hours);
+  } else {
+    ESP_LOGCONFIG(TAG, "Timezone: UTC%+d:%02d", std_hours, std_mins);
+  }
+  if (this->parsed_tz_.has_dst) {
+    int dst_hours = -this->parsed_tz_.dst_offset_seconds / 3600;
+    ESP_LOGCONFIG(TAG, "  DST: UTC%+d, M%d.%d.%d/%" PRId32 " - M%d.%d.%d/%" PRId32, dst_hours,
+                  this->parsed_tz_.dst_start.month, this->parsed_tz_.dst_start.week,
+                  this->parsed_tz_.dst_start.day_of_week, this->parsed_tz_.dst_start.time_seconds / 3600,
+                  this->parsed_tz_.dst_end.month, this->parsed_tz_.dst_end.week, this->parsed_tz_.dst_end.day_of_week,
+                  this->parsed_tz_.dst_end.time_seconds / 3600);
+  }
 #endif
   auto time = this->now();
   ESP_LOGCONFIG(TAG, "Current time: %04d-%02d-%02d %02d:%02d:%02d", time.year, time.month, time.day_of_month, time.hour,
@@ -72,11 +86,6 @@ void RealTimeClock::synchronize_epoch_(uint32_t epoch) {
     ret = settimeofday(&timev, nullptr);
   }
 
-#ifdef USE_TIME_TIMEZONE
-  // Move timezone back to local timezone.
-  this->apply_timezone_();
-#endif
-
   if (ret != 0) {
     ESP_LOGW(TAG, "setimeofday() failed with code %d", ret);
   }
@@ -89,10 +98,10 @@ void RealTimeClock::synchronize_epoch_(uint32_t epoch) {
 }
 
 #ifdef USE_TIME_TIMEZONE
-void RealTimeClock::apply_timezone_() {
+void RealTimeClock::apply_timezone_(const char *tz) {
   // Parse the POSIX TZ string using our custom parser to avoid pulling in scanf (~7.6KB)
-  if (!parse_posix_tz(this->timezone_.c_str(), this->parsed_tz_)) {
-    ESP_LOGW(TAG, "Failed to parse timezone: %s", this->timezone_.c_str());
+  if (!parse_posix_tz(tz, this->parsed_tz_)) {
+    ESP_LOGW(TAG, "Failed to parse timezone: %s", tz);
     // Reset to UTC on parse failure
     this->parsed_tz_ = ParsedTimezone{};
   }
diff --git a/esphome/components/time/real_time_clock.h b/esphome/components/time/real_time_clock.h
index f1f1fcfa8a..055fa7f668 100644
--- a/esphome/components/time/real_time_clock.h
+++ b/esphome/components/time/real_time_clock.h
@@ -23,22 +23,15 @@ class RealTimeClock : public PollingComponent {
   explicit RealTimeClock();
 
 #ifdef USE_TIME_TIMEZONE
-  /// Set the time zone.
-  void set_timezone(const std::string &tz) {
-    this->timezone_ = tz;
-    this->apply_timezone_();
-  }
+  /// Set the time zone from a POSIX TZ string.
+  void set_timezone(const char *tz) { this->apply_timezone_(tz); }
 
-  /// Set the time zone from raw buffer, only if it differs from the current one.
-  void set_timezone(const char *tz, size_t len) {
-    if (this->timezone_.length() != len || memcmp(this->timezone_.c_str(), tz, len) != 0) {
-      this->timezone_.assign(tz, len);
-      this->apply_timezone_();
-    }
-  }
+  /// Set the time zone from a null-terminated string with known length.
+  /// The length parameter is ignored since our parser uses null-terminated strings.
+  void set_timezone(const char *tz, size_t /*len*/) { this->apply_timezone_(tz); }
 
-  /// Get the time zone currently in use.
-  std::string get_timezone() { return this->timezone_; }
+  /// Set the time zone from a std::string.
+  void set_timezone(const std::string &tz) { this->apply_timezone_(tz.c_str()); }
 #endif
 
   /// Get the time in the currently defined timezone.
@@ -73,9 +66,8 @@ class RealTimeClock : public PollingComponent {
   void synchronize_epoch_(uint32_t epoch);
 
 #ifdef USE_TIME_TIMEZONE
-  std::string timezone_{};
   ParsedTimezone parsed_tz_{};
-  void apply_timezone_();
+  void apply_timezone_(const char *tz);
 #endif
 
   CallbackManager<void()> time_sync_callback_;