Let it snow! With each passing week, our weather turns progressively colder. New Jersey’s first snowflakes of the season are now in view. And the Winter Solstice is only a little more than a month away. It is time to start thinking seriously about wintry weather. More specifically: Snow.

While pondering the many uses of “bread and milk,” I had a scientific curiosity.

I wondered if there was one day of the year that tends to be snowier than every other date on the calendar for New Jersey. Sure, there is an average “peak” to wintry weather. (In fact, there are three distinct peaks — more on that in a moment.) But can we pinpoint a single day that represents the height of New Jersey’s snow season?

As a matter of fact, yes we can.

Methodology

To complete this analysis, I queried the Applied Climate Information System, a warehouse of weather and climate data.

I specifically looked at exactly 50 years of snowfall data, from 1971 to 2020. (An admittedly arbitrary choice for period of record, but I wanted a healthy spread of snow observations both geographically and temporally.) Approximately 675 weather stations reported snow data in New Jersey in that time frame.

For the purposes of this project, I marked a calendar day as “snowy” if any single weather station in the state reported at least one inch of snowfall on that date.

The Snowiest Day

There is actually a definitive answer here. With 24 out of 50 years (1971-2020) reporting snow — just shy of half — February 5th is the winner.

And what a funny coincidence: February 5th is also National Weatherperson’s Day. The most important holiday of the entire year!

Second place is February 13th with 23 occurrences. Third is January 21nd at 22. And tied for fourth are January 19th, January 25th, February 4th, and February 6th, all at 21 times in 50 years.

Digging into the Statistics

We can even take all the years of snow data and create a graph. This shows, for each day of snow season in New Jersey (October 4th to May 9th), the percentage of years from 1971-2020 that at least one inch of snow was reported somewhere in New Jersey.

Day-to-day variability is to be expected. That is resolved by the red trendline, representing a 14 point (2 week) moving average. There are some definitive patterns noticeable here.

First, I want to point out that the dataset is basically tri-modal. Meaning there are three definitive peaks in snowstorm activity. One little bump in snowy days around mid-December, leading up to the Winter Solstice. Another occurs in mid to late January, matching with the climatologically coldest temperatures of the year — the “dead of winter”. And another peak occurs in early to mid February, including the highest bar on February 5th.

In total, 178 days out of 366 have seen observed inch-plus snow in New Jersey. That is an impressive 49% of the year in which it has snowed here.

Looking at our snow season from start to finish (i.e. left to right on the graph), it is clear that snow can fall in November. But inch-plus snow is pretty rare in NJ until December.

There is a notable minimum value on December 24th. Christmas Eve. Only 4 of the last 50 years have shown an inch of magical Christmas Eve snow. But 11 Christmas Day snow observations have occurred. That strikes me as an odd outlier, and makes me wonder if there’s some observation bias or other funkiness with the reports here.

You will notice another data minimum on February 29th, due to Leap Day. 4 out of the 13 February 29ths in the survey period reported snow. That comes to about 30%, in line with other nearby dates in late February and early March.

Finally, it is notable how quickly accumulating snow chances disappear beyond the first day of Spring, around March 21st. Snow in April is about as rare as November, at each tail of the graph.

Final Thoughts

Obviously, each winter season is different for New Jersey. And this climatological analysis in no way serves as a short-range or long-range forecast. Just a neat little investigation, proving that common sense largely matches reality when it comes to the timing of peak snow chances in New Jersey.

So stock up on the road salt, wear your pajamas inside-out, and start brewing the hot chocolate. February 5th could be a wintry day!

Dan Zarrow is Chief Meteorologist for Townsquare Media New Jersey. Check out Dan’s weather blog or follow him on Facebook for your latest weather forecast updates.