diff --git a/lib/PayloadFormatter/PayloadFormatter.cpp b/lib/PayloadFormatter/PayloadFormatter.cpp
index 3fbad7c..c92710c 100644
--- a/lib/PayloadFormatter/PayloadFormatter.cpp
+++ b/lib/PayloadFormatter/PayloadFormatter.cpp
@@ -2,7 +2,7 @@
 
 PayloadFormatter::PayloadFormatter(uint8_t numOfRow, uint8_t numOfColumn) : _totalPayloads(0), _currentPayload(0), _numOfRow(numOfRow), _numOfColumn(numOfColumn), _payload(NULL), _length(0)
 {
-  _length = numOfRow * numOfColumn * 2 + 7 + 1;
+  _length = (numOfRow * numOfColumn * 2)/* x2 car il faut deux octets pour une température*/ + 7/*pour la date, le numero de trame et le nombre de lignes et de colonnes*/ + 1/*pour le charactère de fin de ligne*/ + 2/*pour la température exterieure*/;
   _payload = (uint8_t *) calloc(_length, sizeof(uint8_t));
 }
 
@@ -25,7 +25,7 @@ boolean PayloadFormatter::endSession()
   return ret;
 }
 
-int16_t PayloadFormatter::buildPayload(uint8_t **buffer, DateTime *dateTime, double *tempArray, uint8_t numOfRow, uint8_t numOfColumn)
+int16_t PayloadFormatter::buildPayload(uint8_t **buffer, DateTime *dateTime, double externTemp, double *tempArray, uint8_t numOfRow, uint8_t numOfColumn)
 {
   *buffer = _payload;
   if(_currentPayload == _totalPayloads || !_totalPayloads)
@@ -53,8 +53,14 @@ int16_t PayloadFormatter::buildPayload(uint8_t **buffer, DateTime *dateTime, dou
   _payload[5] = dateTime->hour();
   _payload[6] = dateTime->minute();
 
-  //Partie temperature
-  for(int i(7),j(0); j < (_numOfRow * _numOfColumn); i+=2, j++)
+  //Octets 7 et 8 pour la température extérieure
+  //Format Q10.6
+  int16_t q10_6_extern = round(externTemp * pow(2,6));
+  _payload[7] = q10_6_extern >> 8;
+  _payload[8] = q10_6_extern;
+  
+  //Partie temperature interne
+  for(int i(9),j(0); j < (_numOfRow * _numOfColumn); i+=2, j++)
   {
     //Format Q10.6
     int16_t q10_6 = round(tempArray[j] * pow(2,6));
diff --git a/lib/PayloadFormatter/PayloadFormatter.h b/lib/PayloadFormatter/PayloadFormatter.h
index a0ac0f3..1ca373b 100644
--- a/lib/PayloadFormatter/PayloadFormatter.h
+++ b/lib/PayloadFormatter/PayloadFormatter.h
@@ -9,7 +9,7 @@ class PayloadFormatter
     PayloadFormatter(uint8_t numOfRow, uint8_t numOfColumn);
     ~PayloadFormatter();
 
-    int16_t buildPayload(uint8_t **buffer, DateTime *dateTime, double *tempArray, uint8_t numOfRow = -1, uint8_t numOfColumn = -1);
+    int16_t buildPayload(uint8_t **buffer, DateTime *dateTime, double externTemp, double *tempArray, uint8_t numOfRow = -1, uint8_t numOfColumn = -1);
     void startSession(uint8_t totalPackets);
     boolean endSession();