awk 'NR==1{                                                                                     ##### When awk is reading very first line of Input_file, then do following actions.
                print;                                                                          ##### print the complete very first line here.
                next                                                                            ##### next is a built in awk keyword, which tells control NOT to go further and skip all next written statements for current(which is very first line) now.
          }
          {
                split($3, A,":");                                                               ##### Now this statement will be executed apart from the first line, I am using split built in function of awk so split 3rd field of the line whose delimiter is ":" colon and storing it into an array named A.
                if($4/$NF>=3){                                                                  ##### Now as per your requirement, I am checking here whenever 4th field is 3 times of $NF(which indicates value of LAST field of each LINE.) field of the line, if this condition is TRUE then do following actions.
                                if(site_id==$1){                                                ##### Here I am checking for a variable named site_id if it has the sae value as previous one or NOT, if it has same value as the previous line ones then execute following statement.
                                                count++                                         ##### Here increasing the value of variable named count one more now. 
                                               };
                                if(!previous)  {                                                ##### Here I am verfiying the value of variable named previous, previous is a variable which will hold the value of your time's(3rd field) 1st value, so that we could make sure the difference between last line(whenever it was satisfying the condition where $4/$NF>=3 is TRUE) and current line's TIME have only 1 hour or min difference.
                                                previous=A[1]                                   ##### Setting up value of array named previous to array A's 1st value here.
                                               };
                                if(A[1]-previous==1){                                           ##### Checking here time differences of the current time's value and the previous time's value, so difference should be one as per your requirement.
                                                        P=P?P ORS $0 OFS count:$0 OFS count;    ##### If above condition is TRUE then I am setting up the value of variable named P to current line's value with the site id's count. Moreover if P already has value then I am making sure P's value should be appended here successfully.
                                                        Q++;                                    ##### Increasing the value of variable named Q here to one, WHERE variable Q is meant for keeping track if 3 consecutive lines have come to satisfy all conditions then it should print the value of P.
                                                        previous=A[1];                          ##### Setting up variable named previous to the array A's 1st value of current line(time value, do do compare operation again for next line.).
                                                        site_id=$1                              ##### Setting up site_id value to $1(first field) of current line.
                                                    }
                                else           {                                                ##### In case difference condition of A[1]-previous is NOT TRUE then perform following actions please. 
                                                        previous=A[1];                          ##### I am setting value of previous variable to A's first value.
                                                        site_id=$1                              ##### Now setting up site_id's value to first field too.
                                               }
                             }
                else         {                                                                  ##### In case condition of $4/$NF>=3 is NOT TRUE then do following actions.
                                previous=A[1];                                                  ##### Setting up variable named previous's value to array A's 1st value for next line's comparisions.
                                P=Q=""                                                          ##### Nulliying the values of variabes named P and Q. Because already condition os FALSE and we need 3 consecutive lines to be satisfied with the conditions so no need of variable named P and Q any value here.
                             };
                if(Q==3)     {                                                                  ##### When variable Q's value is equal to 3 then do following actions.
                                print P;                                                        ##### printing the value of P, which actually will have those 3 consecutive lines which are satisfying all the conditions successfully.
                                P=""                                                            ##### Nullyfing the value of variable P, so that OLD values shouldn't print again while printing the new ones.
                             };
          }
   '    Input_file                                                                              ##### Mentioning the Input_file here.