diff --git a/include/rtc.h b/include/rtc.h
index 20576580..ffe46da5 100644
--- a/include/rtc.h
+++ b/include/rtc.h
@@ -5,9 +5,17 @@
 #include <Wire.h> // must be included here so that Arduino library object file references work
 #include <RtcDS3231.h>
 
+typedef enum {
+  useless = 0,     // waiting for good enough signal
+  dirty = 1,       // time data available but inconfident
+  reserve = 2,     // clock was once synced but now may deviate
+  synced_LORA = 3, // clock driven by LORAWAN network
+  synced_GPS = 4   // best possible quality, clock is driven by GPS
+} clock_state_t;
+
 int rtc_init(void);
-int set_rtc(uint32_t UTCTime);
-int set_rtc(RtcDateTime now);
+int set_rtc(uint32_t UTCTime, clock_state_t state);
+int set_rtc(RtcDateTime now, clock_state_t state);
 uint32_t get_rtc();
 float get_rtc_temp();
 
diff --git a/src/cyclic.cpp b/src/cyclic.cpp
index 90a1b512..57575c92 100644
--- a/src/cyclic.cpp
+++ b/src/cyclic.cpp
@@ -136,7 +136,7 @@ void do_timesync() {
     now.hour = gps.time.hour();
     now.minute = gps.time.minute();
     now.second = gps.time.second();
-    set_rtc(now);
+    set_rtc(now, synced_GPS);
 #endif
     ESP_LOGI(TAG, "Time synced by GPS to %02d:%02d:%02d", hour(), minute(),
              second());
@@ -153,6 +153,13 @@ void do_timesync() {
   ESP_LOGI(TAG, "Network time request scheduled");
 #endif
 
+// use on board time if board has RTC
+#ifdef HAS_RTC
+  setTime(get_rtc());
+  ESP_LOGI(TAG, "Time synced by RTC to %02d:%02d:%02d", hour(), minute(),
+           second());
+#endif
+
 #endif // TIME_SYNC_INTERVAL
 } // do_timesync()
 
diff --git a/src/lorawan.cpp b/src/lorawan.cpp
index 6477ad0b..d11d8af4 100644
--- a/src/lorawan.cpp
+++ b/src/lorawan.cpp
@@ -456,7 +456,7 @@ void user_request_network_time_callback(void *pVoidUserUTCTime,
   // Update system time with  time read from the network
   setTime(*pUserUTCTime);
 #ifdef HAS_RTC
-  set_rtc(*pUserUTCTime);
+  set_rtc(*pUserUTCTime, synced_LORA);
 #endif
       ESP_LOGI(TAG, "Time synced by LoRa network to %02d:%02d:%02d", hour(),
                minute(), second());
diff --git a/src/main.cpp b/src/main.cpp
index 635e943d..2fb98294 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -175,6 +175,9 @@ void setup() {
 #ifdef HAS_RTC
   strcat_P(features, " RTC");
   assert(rtc_init());
+  setTime(get_rtc());
+  ESP_LOGI(TAG, "Time synced by RTC to %02d:%02d:%02d", hour(), minute(),
+           second());
 #endif
 
   // initialize wifi antenna
diff --git a/src/rtc.cpp b/src/rtc.cpp
index a936faea..3e4cf90b 100644
--- a/src/rtc.cpp
+++ b/src/rtc.cpp
@@ -7,6 +7,8 @@ static const char TAG[] = "main";
 
 RtcDS3231<TwoWire> Rtc(Wire);
 
+clock_state_t RTC_state = useless;
+
 // initialize RTC
 int rtc_init() {
 
@@ -24,6 +26,7 @@ int rtc_init() {
     if (!Rtc.IsDateTimeValid()) {
       ESP_LOGW(TAG, "RTC has no valid RTC date/time, setting to compilation date");
       Rtc.SetDateTime(compiled);
+      RTC_state = useless;
     }
 
     if (!Rtc.GetIsRunning()) {
@@ -32,10 +35,12 @@ int rtc_init() {
     }
 
     RtcDateTime now = Rtc.GetDateTime();
+    RTC_state = reserve;
 
     if (now < compiled) {
       ESP_LOGI(TAG, "RTC date/time is older than compilation date, updating)");
       Rtc.SetDateTime(compiled);
+      RTC_state = useless;
     }
 
     // configure RTC chip
@@ -56,26 +61,28 @@ error:
 
 } // rtc_init()
 
-int set_rtc(uint32_t UTCTime) {
+int set_rtc(uint32_t UTCTime, clock_state_t state) {
   // return = 0 -> error / return = 1 -> success
 #ifdef HAS_RTC
   // block i2c bus access
   while (xSemaphoreTake(I2Caccess, 2 * DISPLAYREFRESH_MS) == pdTRUE) {
     Rtc.SetDateTime(RtcDateTime(UTCTime));
     xSemaphoreGive(I2Caccess); // release i2c bus access
+    RTC_state = state;
     return 1;
   } // while
   return 0;
 #endif
 } // set_rtc()
 
-int set_rtc(RtcDateTime now) {
+int set_rtc(RtcDateTime now, clock_state_t state) {
   // return = 0 -> error / return = 1 -> success
 #ifdef HAS_RTC
   // block i2c bus access
   while (xSemaphoreTake(I2Caccess, 2 * DISPLAYREFRESH_MS) == pdTRUE) {
     Rtc.SetDateTime(now);
     xSemaphoreGive(I2Caccess); // release i2c bus access
+    RTC_state = state;
     return 1;
   } // while
   return 0;