This January was Maine’s coldest since 2009 and one of the coldest on record, especially in the northeastern part of the state. 

The National Weather Service station in Caribou saw its 11th lowest temperature on record since 1939 on Jan. 27 at -30 degrees Fahrenheit. The Portland area saw its ninth lowest temperature on record since 1996 that same day, at -9 degrees. 

The winter of 2009 still stands as the coldest Maine has seen in recent decades, including a record low of -37 in Caribou in January that year. But NWS meteorologist Louise Fode said people were likely struck by this January’s temperatures because they were the coldest in several years. 

“Long-term, we hear about colder periods back when folks are younger. But compared to even the past 10 years, this has certainly been a cold snap,” she said. “It lingers in folks’ memories.”

The average temperature in the Caribou region this January was 6.7 degrees, ranking as the fifth coldest of the last 30 years and in the top 20 since temps were first recorded in 1939. Much of the state also saw several inches more snow than normal. And Caribou had a two-week stretch of days with lows below zero, the eight-longest such cold snap on record. 

January made for a bitter start to the year after one of Maine’s warmest falls on record. 

Warming air and sea temperatures, caused by human use of fossil fuels, are shortening winters, heating summers and otherwise reshaping New England’s seasons. But climate change affects the movement of both hot and cold air, Fode said. 

She said the pattern of the jet stream, which “moves warmer air northward and colder air southward,” is becoming “much more stable – in other words, it doesn’t change as much.” 

“With climate change … we have these periods of time where we have an air mass sitting in one location for a long time,” Fode said. “So we can still have these really cold air masses… and particularly during the winter, it can continue to get colder and colder until the jet stream moves it out.” 

The northeast is still, overall, one of the fastest-warming parts of the country. Data shows that places like Portland are feeling that change more quickly than northern and interior Maine. 

Analysis by the nonprofit Climate Central shows that Portland has seen its longest periods of temperatures below normal shrink by nine days since 1970, while Presque Isle and Bangor’s longest cold snaps have shortened by one day.