On the bus traveling back to San Miguel de Allende after a day spent in Dolores Hidalgo last week, I thought I saw in the sky in the distance, from the bus’s window, a huge, bright, colorful rainbow. I sat up straight in my plush seat, the seat belt restricting my sudden movements, to get a better view.

“Mira!” I said to the dignified gray-haired Mexican hombre next to me who was busy watching the movie.

My Spanish teacher, Edith, has been lecturing me to make more of an effort to strike up Spanish conversations in my daily life here. “Practica, practica, practica!” she tells me. I sheepishly counter her strict instruction with, “But I live alone. And I don’t talk to strangers.”

When the man turned to me, I pointed out the windows on both sides of the bus. By this time the spectacular rainbow was a full, wide semicircle looming high over the highway ahead. I wanted to start a conversation with the man, give it a try at least, say something silly for openers, like, “Look, there’s a pot of gold in that valley! It’s nestled in that winding stream down there, which seems to be the rainbow’s end.” But, of course, I didn’t have the Spanish words for all that.

“Si,” he said, “un arco iris,” and went back to watching the movie.

Inter-city buses here in the central mountains of Mexico are surprisingly luxurious (and even more surprisingly inexpensive), especially for someone like me who spent years commuting to work from New Jersey to New York’s then-shabby Port Authority Bus Terminal in even shabbier buses.

These Mexican buses are modern, comfortable, well-maintained and safe. Before boarding, each passenger is given a small bag containing a snack and their choice of beverage (water, soda, or fruit juice). There’s a clean bathroom on board (designed for slim people, to be sure), and there’s always a movie showing from small screens that drop down from the ceiling. It’s like airline flying; but to me it’s better and surer because it’s safely on the ground.

The movie that so captivated the man sitting beside me – something about a high-stakes basketball game at an American girls’ Catholic high school (subtitled in Spanish) – didn’t interest me at all. As always on these long bus rides, I was captivated instead by the contours of the countryside — the undulating hills, just-tilled chocolaty farm land, and verdant pastures – and the big-big sky.

And this time I was captivated also by the glorious rainbow that our bus approached as though it were the grand entrance to a magical hacienda. The bus was about to fly under the rainbow. I was imagining things. I’d fallen under the rainbow’s spell.

It’s both summertime and the rainy season now in these parts, so the two main ingredients for making rainbows – rain and sunshine – are readily available. (Oh, and, too, the big, unobstructed sky, like a vast screen, on which to see them.) But this was the first such rainbow I’d seen here. What causes them, I wondered?  Wikipedia gave me this answer:

“A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets, resulting in a spectrum of light appearing in the sky.”

These water droplets take the form of a multicolored arc – always red, orange, yellow, green, blue, indigo, and violet, in that order. The French word for rainbow is arc-en-ciel; and in Spanish, as I learned from the man beside me on the bus, it’s arco iris.

Of course this wasn’t the first rainbow I’d ever seen, nor the first that cast a spell on me.

In the summer of 2000, while visiting family in the States from Mali, West Africa, where I’d been living for several years, I borrowed my sister’s Subaru and drove from Denver to northern New Mexico by myself, to explore the possibility of living there. (My sister had said to me, “You’ll like New Mexico. You like third-world countries, and New Mexico is just like a third-world country.”)

I studied northern New Mexico’s landscape as I drove my sister’s car: great swaths of sagebrush, clumps of cacti, low-to-the-ground earthen architecture, distant mountain ranges, big-big sky. I felt myself falling in love.

And then, like magic, ahead of me on the highway as I pointed the car north again, was a huge, wide, multicolor, semicircular rainbow. I saw it as a sign: a welcome mat. I moved to New Mexico the following year.

Of course, if Google had existed to me then, I might have done some quick research beforehand, which might well have changed my mind. Having seen so many cactus plants on my initial, exploratory trip, I’d foolishly assumed northern New Mexico enjoyed year-round summer. (NB: Cactus plants don’t grow outdoors in northern New Jersey, where I’m from.) It wasn’t until I’d settled in and confronted the reality of six-month-long winters and all the powdery snow that Taos (a world-class skiing destination) is so famous for that I realized my mistake.

I can’t bear cold climates.

Blame it on that rainbow on the highway. If I hadn’t seen it and fallen under its spell, perhaps I might have looked farther afield and moved to Arizona. But that would have been a far bigger mistake. The fourteen years I lived in New Mexico (despite the winter’s cold) were some of the best years of my life, and the friends I made there are like family.

So here’s my free advice: Watch out for rainbows. They have the power to change your life – but only for the better.