ESP8266 with relay, following sunset-sunrise times of a hardcoded month

foreverjune.ino

#include <math.h>
#define PI 3.1415926
#define ZENITH -.83

#include <NTPClient.h>
#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <TimeLib.h>

const char *ssid     = "xxx";
const char *password = "xxx";

int foreverthismonth = 6;  // the sunrise-sunset will ALWAYS follow this month

WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP);

float calculateSunrise(int year,int month,int day,float lat, float lng,int localOffset, int daylightSavings) {
    /*
    localOffset will be <0 for western hemisphere and >0 for eastern hemisphere
    daylightSavings should be 1 if it is in effect during the summer otherwise it should be 0
    */
    //1. first calculate the day of the year
    float N1 = floor(275 * month / 9);
    float N2 = floor((month + 9) / 12);
    float N3 = (1 + floor((year - 4 * floor(year / 4) + 2) / 3));
    float N = N1 - (N2 * N3) + day - 30;

    //2. convert the longitude to hour value and calculate an approximate time
    float lngHour = lng / 15.0;      
    float t = N + ((6 - lngHour) / 24);   //if rising time is desired:
    //float t = N + ((18 - lngHour) / 24)   //if setting time is desired:

    //3. calculate the Sun's mean anomaly   
    float M = (0.9856 * t) - 3.289;

    //4. calculate the Sun's true longitude
    float L = fmod(M + (1.916 * sin((PI/180)*M)) + (0.020 * sin(2 *(PI/180) * M)) + 282.634,360.0);

    //5a. calculate the Sun's right ascension      
    float RA = fmod(180/PI*atan(0.91764 * tan((PI/180)*L)),360.0);

    //5b. right ascension value needs to be in the same quadrant as L   
    float Lquadrant  = floor( L/90) * 90;
    float RAquadrant = floor(RA/90) * 90;
    RA = RA + (Lquadrant - RAquadrant);

    //5c. right ascension value needs to be converted into hours   
    RA = RA / 15;

    //6. calculate the Sun's declination
    float sinDec = 0.39782 * sin((PI/180)*L);
    float cosDec = cos(asin(sinDec));

    //7a. calculate the Sun's local hour angle
    float cosH = (sin((PI/180)*ZENITH) - (sinDec * sin((PI/180)*lat))) / (cosDec * cos((PI/180)*lat));
    /*   
    if (cosH >  1) 
    the sun never rises on this location (on the specified date)
    if (cosH < -1)
    the sun never sets on this location (on the specified date)
    */

    //7b. finish calculating H and convert into hours
    float H = 360 - (180/PI)*acos(cosH);   //   if if rising time is desired:
    //float H = acos(cosH) //   if setting time is desired:      
    H = H / 15;

    //8. calculate local mean time of rising/setting      
    float T = H + RA - (0.06571 * t) - 6.622;

    //9. adjust back to UTC
    float UT = fmod(T - lngHour,24.0);

    //10. convert UT value to local time zone of latitude/longitude
    return UT + localOffset + daylightSavings;

    }

float calculateSunset(int year,int month,int day,float lat, float lng,int localOffset, int daylightSavings) {
    /*
    localOffset will be <0 for western hemisphere and >0 for eastern hemisphere
    daylightSavings should be 1 if it is in effect during the summer otherwise it should be 0
    */
    //1. first calculate the day of the year
    float N1 = floor(275 * month / 9);
    float N2 = floor((month + 9) / 12);
    float N3 = (1 + floor((year - 4 * floor(year / 4) + 2) / 3));
    float N = N1 - (N2 * N3) + day - 30;

    //2. convert the longitude to hour value and calculate an approximate time
    float lngHour = lng / 15.0;      
    float t = N + ((6 - lngHour) / 24);   //if rising time is desired:
    //float t = N + ((18 - lngHour) / 24)   //if setting time is desired:

    //3. calculate the Sun's mean anomaly   
    float M = (0.9856 * t) - 3.289;

    //4. calculate the Sun's true longitude
    float L = fmod(M + (1.916 * sin((PI/180)*M)) + (0.020 * sin(2 *(PI/180) * M)) + 282.634,360.0);

    //5a. calculate the Sun's right ascension      
    float RA = fmod(180/PI*atan(0.91764 * tan((PI/180)*L)),360.0);

    //5b. right ascension value needs to be in the same quadrant as L   
    float Lquadrant  = floor( L/90) * 90;
    float RAquadrant = floor(RA/90) * 90;
    RA = RA + (Lquadrant - RAquadrant);

    //5c. right ascension value needs to be converted into hours   
    RA = RA / 15;

    //6. calculate the Sun's declination
    float sinDec = 0.39782 * sin((PI/180)*L);
    float cosDec = cos(asin(sinDec));

    //7a. calculate the Sun's local hour angle
    float cosH = (sin((PI/180)*ZENITH) - (sinDec * sin((PI/180)*lat))) / (cosDec * cos((PI/180)*lat));
    /*   
    if (cosH >  1) 
    the sun never rises on this location (on the specified date)
    if (cosH < -1)
    the sun never sets on this location (on the specified date)
    */

    //7b. finish calculating H and convert into hours
    //float H = 360 - (180/PI)*acos(cosH);   //   if if rising time is desired:
    float H = (180/PI)*acos(cosH);    //   if setting time is desired:      
    H = H / 15;

    //8. calculate local mean time of rising/setting      
    float T = H + RA - (0.06571 * t) - 6.622;

    //9. adjust back to UTC
    float UT = fmod(T - lngHour,24.0);

    //10. convert UT value to local time zone of latitude/longitude
    return UT + localOffset + daylightSavings;

    }

int getSunrise() {
    unsigned long t = timeClient.getEpochTime();
    float localT = calculateSunrise(year(t),foreverthismonth,day(t),51.97,5.66,0,1);
    double hours;
    float minutes = modf(localT,&hours)*60;
    return (((int)floor(hours)*60)+(int)floor(minutes));
}


int getSunset() {
    unsigned long t = timeClient.getEpochTime();
    float localT=fmod(24 + calculateSunset(year(t),foreverthismonth,day(t),51.97,5.66,0,1),24.0); 
    double hours;
    float minutes = modf(localT,&hours)*60;
    return (((int)floor(hours)*60)+(int)floor(minutes));
}

int sunsettoday;
int sunrisetoday;

void updatesuntimes() {
  sunrisetoday = getSunrise();
  sunsettoday = getSunset();
}

void setup() {
  Serial.begin(115200);

  WiFi.begin(ssid, password);

  while ( WiFi.status() != WL_CONNECTED ) {
    delay ( 500 );
    Serial.print ( "." );
  }


  timeClient.begin();
  timeClient.setTimeOffset(3600);

  pinMode(D1, OUTPUT);
  digitalWrite(D1, HIGH);

  updatesuntimes();

}

void loop() {

  timeClient.update();

  unsigned long t = timeClient.getEpochTime();

  int dayminutes = (hour(t)*60)+minute(t);

  if (dayminutes == 5) {
    updatesuntimes();
  }

  Serial.print(dayminutes);
  Serial.print(" ");
  Serial.print(sunrisetoday);
  Serial.print(" ");
  Serial.print(sunsettoday);
  Serial.println();

  if ((dayminutes>sunrisetoday) && (dayminutes<sunsettoday)) {
    // turn on relay 
    digitalWrite(D1, LOW);
  } else {
    // turn off relay
    digitalWrite(D1, HIGH);
  }

  delay(1000);
}