Idaho shivered through its coldest October on record, while Washington weathered its second-coldest October and the coolest in more than a century, according to the National Oceanic and Atmospheric Administration.
Oregon was chilly, too. The month was the fourth-coldest October for the state, according to records that date back to 1895.
The extended region-wide cold snap defied the odds. NOAA’s Climate Prediction Center forecast in September that the outlook favored a warmer than normal October.
Unusual atmospheric conditions caused frigid air to blow down from the Gulf of Alaska, Washington State Assistant Climatologist Karin Bumbaco said. Normally, warmer and wetter air from the south flows into the region, she said.
“It was really different than we would typically see this time of year,” Bumbaco said.
The cold damaged some crops, and the northern winds “made farm work outdoors miserable,” according to the USDA’s late October crop report for Idaho.
The cold October followed a wet and cool September.
The combination was not good, said Snohomish County, Wash., organic farmer Tristan Kelsick.
“We didn’t get the growth we normally get in September,” he said. “It set up an unsuccessful October.”
Klickitat County, Wash., rancher Neil Kayser said the September rain was good for pastures.
“Then October came and froze everything back, and now we’re short on pasture,” he said.
Washington and Oregon’s coasts were cooler than normal, and temperatures got even colder than usual inland.
Idaho’s average temperature for the month was 36.7 degrees. That was 7.4 degrees before average. It broke the record of 37.5 degrees set in 1919.
Idaho’s minimum average temperature of 24.7 degrees also set a record, breaking the old mark by 7.1 degrees.
In Washington, the average temperature of 43 degrees was the second-lowest on record. The average temperature was 4.2 degrees below normal and the coolest since 1905.
In Oregon, the average temperature was 43.2 degrees, the coolest since 1946 and 4.9 degrees below normal.
Northern California — on the coast and inland — was cooler than average, but average temperatures were not close to setting records. The north coast had its 34th coolest October, while the Sacramento drainage region had its 31st coolest.
The odds favor warmer than average temperatures in November, December and January throughout the West, according to NOAA’s Climate Prediction Center.