The main difficulty here is in reading the input. Here is a template
that does that for you by reading the char after each integer read:

  char date[10] ; // date fits in 10 chars
  char separator ; // either a space ' ' or a newline '\n'
  while( scanf("%s%c", date,&separator) > 0 ) {
    // we have a new date
    while(separator!='\n') {
      int temperature ;
      scanf("%d%c",&temperature,&separator);
      // do something with the variable temperature
    }
  }