People wait in line at a Western Union on Columbia Road in Northwest Washington on Thursday. Many are sending money home for Mother’s Day. (Jay Westcott for The Washington Post)

Every day she spends apart from her mother is painful for Marleni Suncín. But there’s something particularly melancholy about this day, especially this year.

Her 80-year-old mother in El Salvador was recently diagnosed with cancer, and her kidneys are failing. Suncín, a resident of Northwest Washington and the mother of a 6-month-old boy, wouldn’t be able to make the trip to be with her mother on one of the most important holidays of the year for families in El Salvador and across much of Latin America: Mother’s Day, celebrated in several countries on May 10.

So on Thursday afternoon, she pushed her infant son, Santiago, in his stroller and stood in line at a cramped Western Union in Northwest to send $300 in cash to her mother. Perhaps with this money, her siblings could send mariachis to serenade her on Friday morning with the classic song “Las Mañanitas.”

“I don’t know if the next year she’ll be with us anymore,” Suncín said. “So I hope that this year she’ll be able to enjoy it.”

Throughout the afternoon, other Central American sons and daughters poured into the tiny Western Union and other nearby money-transfer businesses to send funds to mothers far away.

There was Pedro Job Rivera, who hasn’t seen his Salvadoran mother in 15 years and longs for her chicken soup and warm hugs. There was Nelson Rodriguez, 26, who is still getting used to being so far apart from his mother, having left Honduras about two years ago. There was Amadeo Landaverde, a 38-year-old construction worker from El Salvador whose 7-year-old daughter only remembers meeting her grandmother over Skype.

With the District’s large immigrant community, especially of Central Americans, money-transfer services like these are often in high demand. But only once a year are they quite this busy.

Call it the Mother’s Day effect. In the lead-up to and immediately after Mother’s Day, Western Union records a spike in the amount of money sent from the United States to the rest of the world. Latin America, including Mexico and the Caribbean, leads as the region that receives the most money from the United States for Mother’s Day, according to Western Union.

Over the past six years, May has been the month with the largest dollar amount of remittances to Mexico, Brazil and Guatemala, according to data provided by Dilip Ratha, a lead economist at the World Bank. In other Central American countries and the Caribbean, May is among the peak months for remittances.

In addition, surveys of thousands of Central American migrants by the Center for Latin American Monetary Studies indicated that the primary recipient of remittances throughout the year is a migrant’s mother.

“Nothing compares to Mother’s Day,” said Dora Escobar, who owns a dozen money-transfer businesses in Maryland, in addition to five restaurants.

The first week of May might be a boon for Escobar and other business owners who operate money-transfer services like these. “But for some of us, they might be the saddest days,” Escobar said. “It brings a lot of nostalgia. It makes you think of home.”

There’s something particularly sacred about the role of the mother in Latino cultures, one that is reflected in the importance placed on Our Lady of Guadalupe and other visions of the Virgin Mary. In Aztec culture, mothers preparing for childbirth were considered as courageous and formidable as warriors going into battle, said Belinda Campos, an associate professor in the Department of Chicano/Latino Studies at the University of California at Irvine.

In Spanish, even the words for the act of giving birth are given more weight: “dar a luz,” or “to bring into the light.”

“There’s a saying, ‘madre solo hay una,’ or ‘mother, there is only one,’ ” Campos said. “It’s sort of a way of emphasizing this is who gave you life. . . . You can never pay them back. They gave you life.”

So what kind of celebration could possibly be fit for a giver of life and beacon of light?

Across Latin America, everyone drops what they’re doing to pay homage to their mothers and grandmothers. Extended families gather for a lunchtime feast. Schoolchildren perform programs dedicated to their mothers. In Mexico, churches hold special Masses, some state offices close, and politicians lay flowers at monuments honoring mothers.

Beyond the pomp and circumstance, the holiday is meant to be a time spent together, as a family. In the United States on Mother’s Day, “You’re supposed to give mom a day off, breakfast in bed, some time to herself,” Campos said. “That sounds weird to Latin American ears. . . . They don’t seek that kind of separation; they seek the proximity and the connection.”

So for Latin American immigrants unable to spend the holiday with their mothers, the day can bring feelings of guilt and immense longing for home.

As Suncín waited in the Western Union, she thought about her mother’s sage advice, her wise scolding, the afternoon coffee they loved to share together.

“I am sad because I know she needs me there in person, but if I’m there, then she can’t get the money she needs,” said Suncín, who works part time at an eldercare home. “These are the sacrifices.”

By the late afternoon, the line stretched to the door in the Adams Morgan Western Union, its walls lined with advertisements in Spanish for prepaid phone cards. Taped over the glass in front of the registers were white sheets of paper reminding customers to pay only with cash. On a table display for Digicel phone plans was a cardboard box with perfume samples, for no particular reason.

Inside a Multi Envios store a few streets away in the Mount Pleasant neighborhood, 70-year-old Narciso Molina approached the counter and asked to send money to his grandchildren in El Salvador, “so they can buy something for their mom,” he told the employee.

Molina’s mother died shortly after he moved to the United States about 14 years ago. “I don’t like thinking about it because I want to cry,” he said. But he wants to teach his grandchildren the importance of this day, of honoring their mother.

“The mother is the one who sustains us, who has lived worried about us,” he said. “More than anyone, it’s the mother.”

During the afternoon rush, Latin American money-transfer company Sigue set up a booth in the store with free hats, cans of Coca-Cola and Salvadoran wafer cookies in celebration of Mother’s Day.

“Did you send money for Mother’s Day?” Sigue representative Juan Manuel Jiménez asked customers walking in. Seven-year-old Thalia tugged on the arm of her father, Amadeo Landaverde, and the sales representative offered her a lollipop.

Landaverde, a carpenter who lives in Northeast Washington, had never been away from home when he left his family in El Salvador 20 years ago — and he has returned only once.

“I always think about her, and especially on this day. This is her day, and I wish I could be there,” Landaverde said of his mother. “But that’s life, and you need to be strong and know that being here, they’re better off. We have to struggle from far away, but in our hearts, we are near.”

In the line just in front of him was Pedro Job Rivera, 45, who reminisced about his hometown of Suchitoto in El Salvador, where families passed around tamales and panes con pollo on El Día de Las Madres, celebrating close to the mothers in their lives. He badly wished he could be there to bring a bouquet of roses to his 82-year-old mother, whom he hasn’t seen since he came to the United States 15 years ago.

But above all else, he felt grateful that she was still alive and, hopefully, enjoying her day.

“You want to be with them, but unfortunately you can’t,” he said. “But you never lose hope that you’ll see them again.”