Trying to make a rainfall calculator using Java, but implementing the use of methods and arrays, what am I missing?

public static void showTotal(int[] amountPerMonth)
    {
        int total =0;
        int[] rainfall = new int[12];
        for (int i=0; i<12; i=i+1)
        {
            rainfall[i] = GUI.getInt("Enter rainfall during month " + i);
            total = rainfall[i] + total;
        }
        System.out.print(total);
    }