Boston Weather Records Show Warm, Wet Years Heading Into Winter Usually Followed By Below Average Snowfall
BOSTON (CBS) - It's been quite the rollercoaster the past few years and it seems like the recap of every season is "This was one to remember." 2021 is shaping up to be no exception!
At the start of November, Boston was nearly 13 inches above the average yearly rainfall to date. We can give credit to the wettest July through September stretch ever on record in the city, a whopping 24.54 inches of rain in just those three months!
Typically when you get a lot rain, temperatures will stay cooler thanks to the abundant cloud cover. This year shattered that theory. Boston is on track to be one of the warmest years on record. The city also recorded the warmest meteorological summer (June, July, and August) despite having all of that rain!
So as we turn the page and look towards winter, the question we're all wondering is how does the crazy weather of 2021 impact the upcoming season?
Let's first give some perspective on average snowfall.
Since 1890, Boston's average snowfall is just over 49 inches (49.2 inches to be exact). If you look at the top ten warmest years on record, the snow season that followed averaged 44.2 inches of snow, about 5 inches below average.
And of the top 10 warmest years, 7 were below the snow norm.
If we boil it down to the top ten warmest summers (June through August), the winters that followed average 39.4 inches of snow. That's nearly 10 inches below the average. In fact, only one of those years (2010) had an above average winter of snow.
To summarize this info, warm summers and warm years are followed by below average snowfall about 80% of the time.
Now we have to turn to the recent rain.
Is there a correlation between wet years and snow? Yup!
Looking back at the top ten wettest years on record through early November, only two of those years were followed by above average snowfall. Looking at the numbers, the average snowfall was only 32.3 inches for that ten year stretch. That's about 17 inches below average!
Similar story if you take the top ten "warm season" (May through October) rainfall years. This again resulted in only two cases of above average snowfall. Another data set that points to about an 80 percent chance of below average snowfall.
One last thought - the last three winters have all had less snow than average.
The common statement following these types of years is "we must be due for a big one."
But, if we take the last decade as a whole (2010-2020), it's ranked as one of the top snow averages on record (53 inches per year). In fact, it has been this way for the last three decades dating back to the 1990s.
Massachusetts always brings some forecasting fun to the table. Seems like this year will give us another round!
Each day this week at 5 p.m. on WBZ-TV our weather team will feature different stories looking ahead to this winter, culminating in our annual winter weather forecast with the whole WBZ team on Friday, November 19!