October is the month when we begin accumulating the winter precipitation that brings over 70% of the annual rainfall in our Mediterranean climate. October 2024 brought us 1.14 inches of precipitation; the norm is 1.41 inches.
In examining the precipitation records for October over the last 25 years, nearly two-thirds experienced Octobers that were under the norm. The year with the greatest October precipitation was 2016 with 4.98”. Only three other Octobers in the entire length of the record, which has been kept since 1892, were wetter: 1962, 7.43”, 1950, 5.68”, and 1924, 5.12”. In the entire length of record, three Octobers experienced no precipitation: October 1895, 1917, and 1936. October of 1916 experienced only 0.01” of precipitation. While we received almost 81% of our normal October precipitation, according to the National Weather Service, and despite significant hurricane related rainfall, “the remainder of the contiguous U.S. generally received less than 50% of normal precipitation, with some parts of the eastern U.S. receiving virtually no rainfall during the month.”
What to Expect for the Year Ahead
Experts say that we may be in for a weak La Niña. La Niña is one of three phases of the El Niño Southern Oscillation (ENSO), periodic changes in water temperature that occur in the Pacific Ocean. (La Niña years, for example, are characterized by cooler than average sea surface temperatures while El Niño years are the opposite.)
These fluctuations impact weather across the country — but those effects aren’t uniform. During La Niña, the Pacific Northwest often experiences cooler temperatures and greater precipitation. This year, Southern Oregon has equal chances of experiencing a wetter than normal vs. a drier than normal year, according to the National Oceanic and Atmospheric Administration. (Meanwhile, Northern Oregon is “leaning towards” having a wetter year.)
