Bytes to decimals to an integer?

I started this from a sketch where a PIR detector turns on a light and after 30 seconds the light goes out. This works. Earlier this week I bought a little DS1307 module and hooked it up through I2C to my Arduino Uno. Now I want to only turn on the light in the evening (lets say after 18:00) and if the PIR detector is high. For the DS1307 module I used some code I found here → RTC1307 - Real Time Clock - Combustory
I can read the time from the DS1307 (serial monitor).
The only bit that doesn’t work is this: “if (pirState == HIGH && (hour, DEC) >= 18)” Do I need to convert the “hour”?
Could someone give me some pointers on how I can accomplish this?
This is the complete sketch:

/*
  http://www.bajdi.com
  PIR detector turns on light, light switches automatically off after 30 seconds.
  Light must only turn on in the evening (after 18:00)  
 */

#include <Wire.h>
const int DS1307_I2C_ADDRESS = 0x68;
const int pir = 2;     // the number of the PIR pin
const int light =  13;      // the number of the light pin

unsigned long on;      //start time for pir light on

int pirState = 0;         // variable for reading the pushbutton status

byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;

// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
{
  return ( (val/16*10) + (val%16) );
}



void getDateDs1307()
{
  // Reset the register pointer
  Wire.beginTransmission(DS1307_I2C_ADDRESS);
  Wire.send(0x00);
  Wire.endTransmission();
 
  Wire.requestFrom(DS1307_I2C_ADDRESS, 7);
 
  // A few of these need masks because certain bits are control bits
  second     = bcdToDec(Wire.receive() & 0x7f);
  minute     = bcdToDec(Wire.receive());
  hour       = bcdToDec(Wire.receive() & 0x3f);  // Need to change this if 12 hour am/pm
  dayOfWeek  = bcdToDec(Wire.receive());
  dayOfMonth = bcdToDec(Wire.receive());
  month      = bcdToDec(Wire.receive());
  year       = bcdToDec(Wire.receive());
  
}

void setup() {
  Wire.begin();
  Serial.begin(9600);
  pinMode(light, OUTPUT);      
  pinMode(pir, INPUT); 
}

void loop(){

  getDateDs1307();
  Serial.println("  ");
  Serial.print(hour, DEC);
  Serial.print(":");
  Serial.print(minute, DEC);
  Serial.print(":");
  Serial.print(second, DEC);
  Serial.println("  ");
  Serial.print(month, DEC);
  Serial.print("/");
  Serial.print(dayOfMonth, DEC);
  Serial.print("/");
  Serial.println(year, DEC);
  delay(2000);   //slow down serial monitor for testing
  
  pirState = digitalRead(pir);

  if (pirState == HIGH && (hour, DEC) >= 18) {     
    digitalWrite(light, HIGH);  
    on = millis();
  } 

  unsigned long currentMillis = millis();

  if ((currentMillis - on) > 30000) {
    digitalWrite(light, LOW); 
  }
  
}
if (pirState == HIGH && (hour, DEC) >= 18

The ", DEC" doesn't do what you think, or want. If hour is stored as BCD, then simplyif (pirState == HIGH && hour >= 0x18 should do.

I think it should be 0x12? 18 in hex is 0x12, this works :) Thanks for the help.

18 is the same as 0x12, no need for any conversion. Sorry, I thought your representation was BCD.