Need help with converting Celsius to Fahrenheit in the code
If you are using the Adafruit DHT sensor library, then you can get a
Fahrenheit reading by passing true as an argument to
readTemperature(). C.f. the comment in the source code. For
example:

Serial.print("Temp: ");
Serial.print(dht.readTemperature(true));  // true -&gt; Fahrenheit
Serial.println(" deg. F");


Note that this library offers also the conversion functions
convertCtoF() and convertFtoC().