The two equinoxes and two solstices have long been observed by people on earth, before the establishment of many of today’s religious holidays, before the annual celebrations of independence, and certainly before the creation of bound appointment books and digitalized calendar apps. In today’s terms, the equinox and solstice are roughly determined by the relative orientations of our planet and the sun. The December solstice is the day when there is the least sunlight and the most darkness in the Northern Hemisphere, but the most sunlight and the least darkness in the Southern Hemisphere, because the South Pole is maximally tilted towards the sun. Likewise, the June solstice is the longest day in the Northern Hemisphere but the shortest in the Southern Hemisphere, because the North Pole is closest to the sun. On the other hand, the equinoxes occur when then sun is directly across from the equator, such that the length of day and night are equivalent, regardless of which hemisphere you live in.
In many cultures, the equinox and solstice are a mark of the changing seasons, and an announcement that spring, summer, autumn, or winter has arrived. The reality, however, is that the transition between one season to the next is a gradual and non-linear process, one that teases us and tricks us and tempts us to predict what the weather will bring. Sometimes, the heat of summer seems to linger for too long, making us impatient for the first cool breath of autumn as the weeks stretch past in a languorous haze. Other times, the first leaves and petals of spring unfurl almost overnight, and in a blink of an eye, the season is in full bloom, leaving us wondering when exactly that transition passed us by.
In some ways, it is peculiar that living things can sense that a season has changed. A flock of migratory cranes will set off in a synchronous flap of their bold wings, arranged in an unrehearsed yet remarkably neat formation in the skies. A canopy of leaves will transform from emerald green to warmer hues of yellow ochre and carmine red, until they create a carpet of fading browns underfoot. Later, dormant bulbs, snuggled deep underground in their dark, warm beds of soil, will send up shoots to venture into the sunlight and chilly winds above. How do they know that one season is fading and another one is emerging, even when dark and cloudy days are interrupted by full days of sun, and cooling temperatures are exchanged for one last heat wave?
The ability to sense the changing of the seasons is one that human beings still retain, despite the isolation afforded to us by the prevalence of artificial lighting, concrete roads, and thermostats, and the unrelenting procession of the very human concept of seconds, minutes, and hours each day. No matter how deep within the city you live, even an act as simple as throwing open a window can elicit nostalgia for the season of yesterday and anticipation for the season of tomorrow. Here, we count the ways we perceive that change is in the air, with a focus on New England’s transition from winter to spring.