diff --git a/firmware/lib/cw-commons/CWDateTime.cpp b/firmware/lib/cw-commons/CWDateTime.cpp
index 5645eef..e0aa9f2 100644
--- a/firmware/lib/cw-commons/CWDateTime.cpp
+++ b/firmware/lib/cw-commons/CWDateTime.cpp
@@ -1,11 +1,19 @@
 #include "CWDateTime.h"
 
-void CWDateTime::begin(const char *timeZone, bool use24format, const char *ntpServer = NTP_SERVER)
+void CWDateTime::begin(const char *timeZone, bool use24format, const char *ntpServer = NTP_SERVER, const char *posixTZ = "")
 {
   Serial.printf("[Time] NTP Server: %s, Timezone: %s\n", ntpServer, timeZone);
-  
   ezt::setServer(String(ntpServer));
-  myTZ.setLocation(timeZone);
+
+  if (strlen(posixTZ) > 1) {
+    // An empty value still contains a null character so not empty is a value greater than 1.
+    // Set to defined Posix TZ
+    myTZ.setPosix(posixTZ);
+  } else {
+    // Use automatic eztime remote lookup
+    myTZ.setLocation(timeZone);
+  }
+
   this->use24hFormat = use24format;
   ezt::updateNTP();
   waitForSync();
diff --git a/firmware/lib/cw-commons/CWDateTime.h b/firmware/lib/cw-commons/CWDateTime.h
index d3eb583..6add607 100644
--- a/firmware/lib/cw-commons/CWDateTime.h
+++ b/firmware/lib/cw-commons/CWDateTime.h
@@ -11,7 +11,7 @@ class CWDateTime
   bool use24hFormat = true;
 
 public:
-  void begin(const char *timeZone, bool use24format, const char *ntpServer);
+  void begin(const char *timeZone, bool use24format, const char *ntpServer, const char *posixTZ);
   String getFormattedTime();
   String getFormattedTime(const char* format);
 
diff --git a/firmware/lib/cw-commons/CWPreferences.h b/firmware/lib/cw-commons/CWPreferences.h
index d1d7a67..1fbd61b 100644
--- a/firmware/lib/cw-commons/CWPreferences.h
+++ b/firmware/lib/cw-commons/CWPreferences.h
@@ -24,6 +24,7 @@ struct ClockwiseParams
     const char* const PREF_NTP_SERVER = "ntpServer";
     const char* const PREF_CANVAS_FILE = "canvasFile";
     const char* const PREF_CANVAS_SERVER = "canvasServer";
+    const char* const PREF_MANUAL_POSIX = "manualPosix";
 
 
     bool swapBlueGreen;
@@ -38,6 +39,7 @@ struct ClockwiseParams
     String ntpServer;
     String canvasFile;
     String canvasServer;
+    String manualPosix;
 
 
     ClockwiseParams() {
@@ -65,6 +67,7 @@ struct ClockwiseParams
         preferences.putString(PREF_NTP_SERVER, ntpServer);
         preferences.putString(PREF_CANVAS_FILE, canvasFile);
         preferences.putString(PREF_CANVAS_SERVER, canvasServer);
+        preferences.putString(PREF_MANUAL_POSIX, manualPosix);
     }
 
     void load()
@@ -81,6 +84,7 @@ struct ClockwiseParams
         ntpServer = preferences.getString(PREF_NTP_SERVER, NTP_SERVER);
         canvasFile = preferences.getString(PREF_CANVAS_FILE, "");
         canvasServer = preferences.getString(PREF_CANVAS_SERVER, "raw.githubusercontent.com");
+        manualPosix = preferences.getString(PREF_MANUAL_POSIX, "");
     }
 
 };
diff --git a/firmware/lib/cw-commons/CWWebServer.h b/firmware/lib/cw-commons/CWWebServer.h
index c5f95f3..12590c6 100644
--- a/firmware/lib/cw-commons/CWWebServer.h
+++ b/firmware/lib/cw-commons/CWWebServer.h
@@ -123,6 +123,8 @@ struct ClockwiseWebServer
         ClockwiseParams::getInstance()->canvasFile = value;
       } else if (key == ClockwiseParams::getInstance()->PREF_CANVAS_SERVER) {
         ClockwiseParams::getInstance()->canvasServer = value;
+      } else if (key == ClockwiseParams::getInstance()->PREF_MANUAL_POSIX) {
+        ClockwiseParams::getInstance()->manualPosix = value;
       }
       ClockwiseParams::getInstance()->save();
       client.println("HTTP/1.0 204 No Content");
@@ -157,6 +159,7 @@ struct ClockwiseWebServer
     client.printf(HEADER_TEMPLATE_S, ClockwiseParams::getInstance()->PREF_NTP_SERVER, ClockwiseParams::getInstance()->ntpServer.c_str());
     client.printf(HEADER_TEMPLATE_S, ClockwiseParams::getInstance()->PREF_CANVAS_FILE, ClockwiseParams::getInstance()->canvasFile.c_str());
     client.printf(HEADER_TEMPLATE_S, ClockwiseParams::getInstance()->PREF_CANVAS_SERVER, ClockwiseParams::getInstance()->canvasServer.c_str());
+    client.printf(HEADER_TEMPLATE_S, ClockwiseParams::getInstance()->PREF_MANUAL_POSIX, ClockwiseParams::getInstance()->manualPosix.c_str());
 
     client.printf(HEADER_TEMPLATE_S, "CW_FW_VERSION", CW_FW_VERSION);
     client.printf(HEADER_TEMPLATE_S, "CW_FW_NAME", CW_FW_NAME);
diff --git a/firmware/lib/cw-commons/SettingsWebPage.h b/firmware/lib/cw-commons/SettingsWebPage.h
index 5798be4..7bd6272 100644
--- a/firmware/lib/cw-commons/SettingsWebPage.h
+++ b/firmware/lib/cw-commons/SettingsWebPage.h
@@ -127,6 +127,14 @@ const char SETTINGS_PAGE[] PROGMEM = R""""(
           save: "updatePreference('canvasServer', serverAddress.value)",
           property: "canvasServer",
           exclusive: "cw-cf-0x07"
+        },
+        {
+          title: "Posix Timezone String",
+          description: "To avoid remote lookups, provide a Posix string that corresponds to your timezone. Leave empty to obtain this automatically from the server. <a href=\"https://github.com/nayarsystems/posix_tz_db/blob/master/zones.csv\">Click here for a list.</a>",
+          formInput: "<input id='posixString' class='w3-input w3-light-grey' name='posixString' type='text' placeholder='Manual Posix String' value='" + settings.manualposix + "'>",
+          icon: "fa-globe",
+          save: "updatePreference('manualPosix', posixString.value)",
+          property: "manualPosix"
         }
       ];
 
diff --git a/firmware/src/main.cpp b/firmware/src/main.cpp
index e148067..a5b4f74 100644
--- a/firmware/src/main.cpp
+++ b/firmware/src/main.cpp
@@ -96,7 +96,10 @@ void setup()
   if (wifi.begin())
   {
     StatusController::getInstance()->ntpConnecting();
-    cwDateTime.begin(ClockwiseParams::getInstance()->timeZone.c_str(), ClockwiseParams::getInstance()->use24hFormat, ClockwiseParams::getInstance()->ntpServer.c_str());
+    cwDateTime.begin(ClockwiseParams::getInstance()->timeZone.c_str(), 
+        ClockwiseParams::getInstance()->use24hFormat, 
+        ClockwiseParams::getInstance()->ntpServer.c_str(),
+        ClockwiseParams::getInstance()->manualPosix.c_str());
     clockface->setup(&cwDateTime);
   }
 }