Dartmouth Mythbusters: When Will It Really Be Warm?
We’ve all heard euphoric predictions of warm weather come spring term, but those of us with some knowledge of the Northeast’s weather patterns shake our heads in scorn at such wishful thinking.
So when does winter truly end in Hanover? The official first day of spring is March 20, but by then the ice pack covering campus has only just began to thaw. Indeed, the grim, icy layer of mud is not so far removed from the vistas of rocky, glacial ice that Leif Ericson explored and dubbed Helluland in his early explorations of the Americas.
And what temperature qualifies as “warm”? Here in balmy New Hampshire, we might be inclined to call a temperature of 60 degrees T-shirt weather, but our friends in the Southwest — more accustomed to temperatures in the 80s, 90s, and even into the triple digits — might balk at such a statement. We will set the bar at scientific room temperature — 68 degrees Fahrenheit.
To determine when spring will come, we must first look to the historical record of weather conditions. Freezing weather can persist until June — indeed, in one year, temperatures of 32 degrees continued until June 4. Throughout April, historical average lows remain in the high 20s and low 30s, while average highs usually fail to break into the mid-60s and — for the first two-thirds of the month — hover in the 50s or 40s.
While the record for daily high temperatures in April is in the 90s, the averages don’t scrape even close to that level. We should therefore add a new component to our search: consistency. We cannot gauge our estimation of warmth from the record highs and lows, but must instead work from the averages over a period of time. In other words, our final prediction will be the first time a daily high temperature of 68° is reached on average for a period of three consecutive days.
For such conditions to exist, we must look to May. On average, the daily high temperature is 68 degrees on May 11, 68 degrees again on May 12 and May 13, 70 degrees on May 14 and May 15, down again to 69 degrees on May 16 and in the high 60s or low 70s for the remainder of the month. During that same period, average low temperatures tend to be in the mid-40s. Therefore, it will not be “warm” under our subjective definition until mid-May.
Students in Collis on Monday afternoon, responding to what was absolutely a scientific poll with a large and representative sample size, predicted that the weather would breach into the low 60s in late April and early May, meaning that most have a relatively realistic — if a little rosy — perspective on Hanover’s weather prospects.
And what of precipitation? Well, as temperatures can continue to be below freezing into June, and snow, too, can continue that late into the year. Snowstorms in May are not at all implausible, although it is likely that any snow that late in the year would melt in short order. We can reasonably expect, however, that most snowfall has already passed us by. It is relatively unlikely that we will see major snowfall beyond April, but that doesn’t mean you should stop worrying about precipitation. The rains in April through June aren’t quite the docile “April Showers” of popular imagination — indeed, major storms frequently move down through the valleys of the Northeast during the spring, wreaking havoc and keeping skies resolutely overcast.
We hope our weather update hasn’t brought about too many April blues for you, our dear readers. We suggest you learn to love the rain and mud and grow to appreciate the frolicking about that such weather can so gleefully promote — if you’re okay with getting your boots a little dirty.
Besides, it won’t be too long until you’re asking us when the first snow of next winter will be.