Java program to find max value in an array is printing multiple values

It’s printing out a number every time it finds one that is higher than the current max (which happens to occur three times in your case.) Move the print outside of the for loop and you should be good.

for (int counter = 1; counter < decMax.length; counter++)
{
     if (decMax[counter] > max)
     {
           max = decMax[counter];
     }
}

System.out.println("The highest maximum for the December is: " + max);