"Somewhere, sometime, the first rains helped lead to the first life. Whether those primordial cells were stirred up in Charles Darwin's 'warm little pond' or originated in hydrothermal vents deep in the seafloor as many scientists today hypothesize, the first life required the rain.

"Water alone is not enough, [David] Grinspoon [chair of astrobiology at the Library of Congress] explains. Water is 'out there,' too — in the atmosphere of Venus and in the polar caps of Mars — but it does not sustain a living world on either of those planets. To become our life force, water also had to build up in the skies, move along with the wind, and pour back to the surface, replenishing the waters, lands, and beings again and again.

"From those cataclysmic torrents 4 billion years ago to the hydrologic cycle that slakes aquifers, soil, and rivers day after day, rain, as the source of Earth's water, became the wellspring of life. 'Sunshine abounds everywhere,' the American nature writer John Burroughs wrote in a paean that soaked nine pages of Scribner's magazine in 1878, 'but only where the rain or dew follows is there life.'

"Life, and something more. Humans have a natural affinity for rain, grounded in its necessity for civilization and agriculture. Thomas Jefferson constantly watched the sky from his Monticello home in Virginia, where cerulean thunderclouds build along the Blue Ridge Mountains as if matched by Picasso. Jefferson fretted over cloudless days the way that all farmers do. He found relief when storms returned, carrying moisture from the yet-mysterious West. His letters often closed with a word on the rain — or the lack. 'Not enough rain to lay the dust,' he would lament. Or he'd gratefully share news of 'a fine rain,' 'a divine rain,' 'plentiful showers.'

"Sometimes, after writing to his fellow statesman James Madison, who measured rain in a tin cup nailed to the front gate at his Montpelier estate thirty miles northeast, Jefferson would hold off sealing the letter until morning so he could report the overnight showers at Monticello. 'The earth has enough,' Jefferson concluded after one such update, 'but more is wanting for the springs and streams.'

"Wanting is apropos, a hint at something more. For the story of rain is also a love story — the tale of 'certain unquenchable exaltation' that the poet William Carlos Williams felt as he beheld his storied red wheelbarrow

"glazed with rain water.

"And for all of history, it has inspired all the excitement, longing, and heartbreak that a good love story entails. The first civilizations rose and fell with the rain, which has helped shape humanity since our earliest ancestors radiated out of Africa when the rainfall tapered off and the forests turned to savanna grasslands. Every culture had its own way of worshipping rain, from Mesoamerican cave paintings exalting rain deities to modern Christian governors who call prayer for a storm.

"Rain and two more of its wondrous pride — clouds and rainbows — have inspired writers, painters, and poets for thousands of years. Homer's Iliad is thick with clouds, as is much of the ancients' poetry and prose. The modern poets wrote unforgettably of rain — what Conrad Aiken called the 'syllables of water.' Other authors awakened in its absence: Mary Austin, Willa Cather, and Wallace Stegner all found their muse in thirsting lands. True, the sun and the wind inspire. But rain has an edge. Who, after all, dreams of dancing in dust? Or kissing in the bright sun?"