After our Christmas snow, the theme of the weather over the next 7-10 days is going to be the cold. While Tuesday’s temperatures will be below average, we’re going significantly below average for the rest of the week and into the weekend.

I am not a fan of hyperbole – and writing about cold weather in Maine in late December is like writing about heat in Texas in July.  But there are times when the cold is more noteworthy than others, and later this week, the chill in the air will break some records.

In terms of forecasting challenges the biggest issue is just how cold we stay each day and become each night. It looks like Thursday will be the coldest day of the week. Temperatures will not get out of the single numbers along the coast and will actually stay below zero in the mountains.  

To give this cold a reference point we have to go back about 70 years. If we look back at December 28th, 1946 we find some interesting data. On that day temperatures reached a high of 11 in Portland and  a raging snowstorm dropped 21 inches of snow. The snow was so light and fluffy  it melted to about mere three-quarters of an inch.

A snowstorm struck Maine in late December 1946 with about 2 feet of snow, there was 19 inches of snow on the ground on December 28th. Dave Epstein

This year the high temperature for December 28th in Portland will be about 5 or 6 degrees above zero.

A cold week is in store through the end of the year and to start 2018. Dave Epstein

December 28th In Perspective

The chart below shows other years when December 28th was cold.  I was surprised when I looked at the data to see very few years when temperatures stayed in the teens all day. So the fact that Thursday’s high is forecast to be near 5 is amazing!  If it happens, it would be one of the few days ever recorded when temperatures have stayed that cold the entire day, not only on December 28th, but any time.

Temperatures haven’t been this cold on December 28th in many years. Dave Epstein

Coldest Days Ever

So it’s a pretty sure bet Thursday will break the daily record, but what about comparing that day to others. After all, it’s just one day. If we widen the search to include all the cold days of winter we find the coldest of the cold days, listed below. When you consider there are over 10,000 winter days with records in Portland and these are the top 30, we start to gain some understanding of a truly a cold day.  Back on January 15th, 2004 Portland managed to reach a high 3 degrees.  This is the last time we had one of these super cold days. Here comes another one Thursday.

The top 30 coldest high temperature days in Portland. Dave Epstein

The cold will relax tiny bit at the end of the week, but we’re still going to be way below average and nowhere near freezing. There might be some snow over the weekend if a system comes close enough, but there’s also a chance it will go out to sea.

This cold weather pattern appears like it’s going to last at least into the first week of the new year and perhaps into the second as well. If your pipes typically freeze and very cold weather you’ll want to do whatever you need to do in order to prevent that from happening. Even if you like winter, you might be ready for a January thaw before this stretch is over.