diff --git a/DHT.cpp b/DHT.cpp
index 86ad91c..cbf9643 100644
--- a/DHT.cpp
+++ b/DHT.cpp
@@ -31,15 +31,15 @@ void DHT::begin(void) {
   DEBUG_PRINT("Max clock cycles: "); DEBUG_PRINTLN(_maxcycles, DEC);
 }
 
-//boolean S == Scale.  True == Fahrenheit; False == Celcius
-float DHT::readTemperature(bool S, bool force) {
+//boolean isFahrenheit: True == Fahrenheit; False == Celcius
+float DHT::readTemperature(bool isFahrenheit, bool force) {
   float f = NAN;
 
   if (read(force)) {
     switch (_type) {
     case DHT11:
       f = data[2];
-      if(S) {
+      if(isFahrenheit) {
         f = convertCtoF(f);
       }
       break;
@@ -52,7 +52,7 @@ float DHT::readTemperature(bool S, bool force) {
       if (data[2] & 0x80) {
         f *= -1;
       }
-      if(S) {
+      if(isFahrenheit) {
         f = convertCtoF(f);
       }
       break;
diff --git a/DHT.h b/DHT.h
index d81f6db..ffae7c6 100644
--- a/DHT.h
+++ b/DHT.h
@@ -39,10 +39,10 @@ class DHT {
   public:
    DHT(uint8_t pin, uint8_t type, uint8_t count=6);
    void begin(void);
-   float readTemperature(bool S=false, bool force=false);
+   float readTemperature(bool isFahrenheit=false, bool force=false);
    float convertCtoF(float);
    float convertFtoC(float);
-   float computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit=true);
+   float computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit=false);
    float readHumidity(bool force=false);
    boolean read(bool force=false);
 
diff --git a/examples/DHTtester/DHTtester.ino b/examples/DHTtester/DHTtester.ino
index ae6c41a..e00f95d 100644
--- a/examples/DHTtester/DHTtester.ino
+++ b/examples/DHTtester/DHTtester.ino
@@ -48,10 +48,10 @@ void loop() {
     return;
   }
 
-  // Compute heat index in Fahrenheit (the default)
-  float hif = dht.computeHeatIndex(f, h);
-  // Compute heat index in Celsius (isFahreheit = false)
-  float hic = dht.computeHeatIndex(t, h, false);
+  // Compute heat index in Celsius (the default)
+  float hif = dht.computeHeatIndex(t, h);
+  // Compute heat index in Fahrenheit (isFahreheit = true)
+  float hic = dht.computeHeatIndex(f, h, true);
 
   Serial.print("Humidity: ");
   Serial.print(h);