Rainfall Report: December 2007
It's not going to rain today. So we'll finish with 8.61 inches of rain in December. That breaks down as:
-24 days with measurable precipitation
-15 days over a tenth of an inch
-5 days over half an inch
-2 days over an inch.

These figures are from my preferred station, in the middle of the city. The number you'll most often see quoted comes from PDX, but that's on the northeast edge of the city. There, the December total was 7.57, a total lower than at all but one of the 40 or so City of Portland HYDRA Rainfall Network gauges. "Normal" December value for the airport is 5.54 inches, but I'm not sure how valuable this figure is – it's the average for the period 1971-2000.