Rounded to the nearest inch, there are 66 inches or precipitation.
Look at the numbers after the decimal point. Do they round up or down? In normal circumstances, would it round to 0, or to 100? It wouldn't round to 100. Anything 50 and above would round to 100, and this is not 50, nor is it more than 50.
So this rounds to the previous number, which is 66.