(Editor's note: To see September's weather summary, click here)
If you're old enough -- or young enough -- to remember trick-or-treating on Halloween 1994 in Portland, the memory is probably a little sodden.
The National Weather Service measured a record 2.44 inches of rain that day. As any of the soggy goblins, wet devils and soaked kitty cats will tell you, much of that rain seemed to fall just after the Halloween candy bags came out.
No surprise: At the beginning of October, the probability of rain on each day is about 30 percent. By the end of the month, the probability rises to 50 percent, says George Taylor of the Oregon Climate Service.
Four days before Halloween that year, on Oct. 27, another daily rainfall record was set -- also at 2.44 inches. October is when storms race in from the Pacific Ocean, leaving the bulk of their moisture -- 100 to 200 inches a year -- on the Oregon coast and in the coastal mountains.
The air warms and dries a bit as it passes over the inland valleys, which results in rainfall of 30 to 60 inches.
As the moisture passes to the east, it slams into the foothills of the Cascades and then the Cascade crest, which squeezes out more moisture, with rainfall averages of 80 to 120 inches. Eastern Oregon gets what's left, about 5 to 30 inches, with more rain and snow falling at higher elevations.