March Weather: In Like a Lion, Out Like a Lamb

spring lambs
Chris Cheadle / All Canada Photos / Getty Images

March comes in like a lion and goes out like a lamb.

What's the meaning behind this popular piece of folklore?

If you've ever heard or used this expression before, you know that in it, the "lion" is a metaphor for the snowstorms, rainstorms, blustery winds, and generally ferocious weather typical of early March; while the calm, quiet conditions that lead into April are likened to a lamb. While there's no weather law that says the start of March will always be unsettled and its end will always be serene, there is an explanation for why this typically occurs.

March's arrival is associated with spring--a transitional season when the cold air of winter is challenged by warmer air which begins returning to the Northern Hemisphere thanks to the sun's increasing ability to more directly heat the earth's surface this time of year (see "Earth's Seasons"). In short, this competition of temperatures leads to tumultuous weather. However, by the month's close, the cold air has typically moderated enough to where there's no longer as great a temperature difference between it and the warmer air masses. 

There happens to be another, non-weather-related explanation for why these two animals are linked to March--astronomy. At the beginning of March, the constellation Leo (the lion) dominates the Northern Hemispheric sky. But by March's end, Aries (the ram, or lamb) has taken over.