The Coldest Day in the Pacific Northwest

In an article for the Idaho Statesman about climate change impacts in the Pacific Northwest, Rocky Barker interviewed Philip Mote – the director of the Oregon Climate Change Research Institute and Oregon Climate Services, and the lead author of the Pacific Northwest Chapter of the 2013 U.S. National Climate Assessment, where this statement was made:

Mote points to one of the data sets of his University of Idaho colleague John Abatzoglou. 'When he looked at the coldest day of the year a lot of the stations have temperatures 10 degrees warmer than they were in the early part of the 20th Century,' Mote said.

Well, according to the NOAA National Weather Service database, among the 10 climate sub-regions in the Pacific Northwest that have climate records for the “coldest day of the year” dating back before 1940, there is only one significant trend toward a warming in the coldest day of the year since records began (this is in the Medford Area, OR).  This is offset by one region with a significant trend toward cooling in the coldest day of the year since records began (Burns Area, OR).  And the remainder of the climate sub-regions in Washington, Oregon, and Idaho have no significant trends in the year's coldest day.

And that single significant warming trend for the small Medford climate sub-region in southwestern Oregon is only 4.5º F/century, not 10º F/century.  The cooling trend right next-door in southeastern Oregon's Burns climate sub-region is -11º F/century.  And, as noted already, the remainder of the long-term data throughout the Pacific Northwest shows no significant trend.

This climate realism is consistent with the fact that wintertime minimum temperatures for the Northwest have no significant trend since the first half of the 20th century ended, according to the NOAA National Climatic Center Database.  Nor has there been a significant trend since 1970, or during the last three decades.

In the future, the Idaho Statesman should engage in less climate sensationalism and instead adopt a far more critical assessment of what is actually happening in the Pacific Northwest.