Interesting. I notice the same for December. Shows 11.0" but we had 9.6"...it added November 30th 1.4. I wonder if they can fix it? Whenever you have snow on the last day of the month it will make the next month wrong lol.
Interestingly, it still counts the snow properly for the last day of the month (ie Nov 3.5, Dec 11.0...should be Nov 3.5 Dec 9.6. And then Jan 6.4, Feb 7.5...should be Jan 6.4, Feb 6.2). So anytime measurable snow falls on the last day of the month, it counts it twice. Although that's only an f6 issue, climate reports remain correct.