In the Pacific Northwest, rainy weather is a fact of life, but last month’s precipitation will go down in the record books.
The National Weather Service measured 8.22 inches of rainfall at Pearson Field — making it the wettest October on record and well above the historic average.
Based on the 30-year average, 1980 to 2010, the city typically gets about 3.24 inches of rain during October.
Previously, Vancouver’s rainiest October was in 1997, when 7.37 inches of rain fell. The third-rainiest October was in 1955 with 7.25 inches.
Except for a wet Oct. 13, most days brought a half inch or less of rain.
“We’ve had a pretty active period in the tropics, particularly in the western Pacific, that may have injected a fair amount of moisture into the jet stream,” said Jon Bonk, a meteorologist at the weather service. “We didn’t have very much variation in our weather pattern. The storm track was aimed at the Pacific Northwest for the month of October.”
October also saw the most rainy days of any October on record with 29 days with measurable rain out of 31— four more than the 2005 record of 25 days.
On Oct. 13, when storm systems associated with Typhoon Songda hit Southwest Washington, 2.06 inches of rain fell on Vancouver, making it the wettest day of the month. Still, the subsequent storms that meteorologists predicted would hit Southwest Washington with historic force delivered much softer impacts than expected.
Bonk said the area is trending toward a weak La Niña, “which in the past has oftentimes meant cool and wetter weather than the 30-year normal.”
At 8.22 inches, October was rainier than even the typically rainiest months of the year, November and December, when an average of 5 to 5.5 inches of rain fall. Still, it’s about half of the all-time record of 16.03 inches set in December 2015.
