diff --git a/ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/ESPMegaProOS.cpp b/ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/ESPMegaProOS.cpp
index d1a9c41..44b7f07 100644
--- a/ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/ESPMegaProOS.cpp
+++ b/ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/ESPMegaProOS.cpp
@@ -183,14 +183,14 @@ bool ESPMegaPRO::updateTimeFromNTP()
     return true;
 }
 
-#include <sstream>
-
-void ESPMegaPRO::setUTCOffset(int offset)
+/**
+ * @brief Sets the timezone for the internal RTC.
+ * 
+ * @note This function takes POSIX timezone strings (e.g. "EST5EDT,M3.2.0,M11.1.0").
+*/
+void ESPMegaPRO::setTimezone(const char* offset)
 {
-    std::ostringstream oss;
-    oss << "UTC" << (offset >= 0 ? "+" : "") << offset;
-    setenv("TZ", oss.str().c_str(), 1);
-    tzset();
+    setenv("TZ", offset, 1);
 }
 
 /**
diff --git a/ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/ESPMegaProOS.hpp b/ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/ESPMegaProOS.hpp
index 2721a58..f78bc86 100644
--- a/ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/ESPMegaProOS.hpp
+++ b/ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/ESPMegaProOS.hpp
@@ -52,7 +52,7 @@ class ESPMegaPRO {
         void enableIotModule();
         void enableInternalDisplay(HardwareSerial *serial);
         void enableWebServer(uint16_t port);
-        void setUTCOffset(int offset);
+        void setTimezone(const char* offset);
         rtctime_t getTime();
         void dumpFRAMtoSerial(uint16_t start, uint16_t end);
         void dumpFRAMtoSerialASCII(uint16_t start, uint16_t end);
diff --git a/ESPMegaPRO-OS-SDK/src/main.cpp b/ESPMegaPRO-OS-SDK/src/main.cpp
index 03572b6..d73714b 100644
--- a/ESPMegaPRO-OS-SDK/src/main.cpp
+++ b/ESPMegaPRO-OS-SDK/src/main.cpp
@@ -163,7 +163,7 @@ void setup()
 {
     ESP_LOGI("Initializer", "Starting ESPMegaPRO OOP demo");
     espmega.begin();
-    espmega.setUTCOffset(7);
+    espmega.setTimezone("UTC-7");
     ESP_LOGI("Initializer", "Enabling IOT module");
     espmega.enableIotModule();
     ESP_LOGI("Initializer", "Enabling Ethernet");