I remember my first-grade teacher, Ms. Neely, telling our class that "March comes in like a lion and goes out like a lamb." I now understand that this old saw is based on the fact that winter turns to spring during the month, but I grew up outside Syracuse, N.Y., where even late March tends to be quite leonine, so it baffled me endlessly as a child.
In Washington this year, March managed to go out in a vaguely lamb-ish way. A string of warmer days at the end still left the average temperature for the month at 43.8 degrees, according to National Weather Service data, three degrees below the historical average and considerably cooler than recent years. The average temperature last March was a record-high 56.8.
Large temperature variations from year to year have significant implications, most obviously for farmers and gardeners but also for utility companies estimating energy use, city managers budgeting for snow and sports teams worrying about scheduling. Are we getting any better at predicting the weather weeks or months in advance?
Before getting to the science, it's important to recognize that there have been false starts and inflated claims in the business of long-term weather forecasting.
Consider the most famous American weather prognosticators, the Farmers' Almanac, published in Lewiston, Maine, and the Old Farmer's Almanac, produced in Dublin, N.H. The writers of these venerable books claim to use top-secret formulas, and followers of the New Hampshire version claim it is 80 percent accurate.
It's impossible, however, to fully assess the books' accuracy, because many of their predictions read like a meteorological fortune cookie: vague enough to accommodate a wide range of weather. Both publications, for example, tend to make such predictions as "sunny, cool" in four- or five-day chunks. In any given workweek, there are usually periods of sun and some temperature variation. Does that make the prediction correct?