Weeks before the Brooklyn Botanic Garden updated CherryWatch, the online tracker that documents the progress of a majority of the garden’s 220 cherry blossom trees, staff members noticed that some people had already begun to check the website for the first signs of spring.

“People will sort of jump the gun and see that we’ve turned on the map even before we’ve officially announced it,” said Elizabeth Reina-Longoria, the communications director at Brooklyn Botanic Garden. Once people see the first blossoms appear on the map, which usually occur sometime in March, there is a flood of regular visitors to the site. She said that the spirit was very much: “‘It’s on! It’s game time!’”

For many New Yorkers — and for some former city dwellers, too — the map serves a practical purpose as well as a more whimsical one. It is a handy tool for visitors to use in planning their travels and to ensure that they can see the maximum number of cherry blossoms when they go. (At Brooklyn Botanic Garden, there is a period of about five to six weeks in which different species and cultivars of trees are flowering.) But over the years, monitoring the tree tracker has become its own springtime rite. Some refresh the site almost as regularly as they would Instagram or Twitter.

“When I lived in New York City, I absolutely checked on a daily basis,” said Christine Amorose Merrill, 34, who now lives in San Diego and works in ad sales. She plans to visit New York’s cherry blossoms sometime this spring, as has become her annual tradition. But, she said, “Frankly, I just find it really fun to see all of the little icons turn to pink and wonder about whose job it is to keep it updated.”

Indeed, the map has its aesthetic charms. Though it is more technologically advanced than it was when the Brooklyn Botanic Garden introduced it in 2006 — at the time, it was a graphic that staff members would manually update every day — the interactive map still recalls the early days of the internet. On a 2-D map of the garden, prebloom buds are represented by pale green dots that turn into pink, and then purple, flower icons. Trees past their peak turn to dark green dots.

“There’s something nice about how simple it is — it’s really low-fi,” said Jackie Liu, 26, a user experience product designer who lives within walking distance of the garden. She tends to keep the blossom map in a tab on her laptop to revisit every few days.

“It is genuinely such a joyful part of being online,” said Meredith Carey, who works as the deputy editor at TripAdvisor. (She does not work with the Brooklyn Botanic Garden in her role.) When she shared a screenshot of the map on her Instagram Stories last week, she said, several friends messaged her looking forward to planning visits this spring.

As for whose job it is to monitor the buds, it is usually the same one or two people who walk the grounds every weekday and take a look themselves, Ms. Reina-Longoria said. It’s a similar case with the Central Park Conservancy’s tracker, which went live for the first time this season after the success of an interactive map for the park’s fall foliage. According to a spokesman for the conservancy, a team of people who maintain Central Park’s 18,000 trees report back on which cherry blossoms are in bloom so the tracker can be updated.

In Washington, D.C., David Coleman’s cherry blossom tracker, which he started around 2010, has about 42,000 followers on Facebook who read his regular reports on the trees. Once buds begin to peek through in late February and March, Mr. Coleman, a professional travel photographer, typically hits the pavement every few days to capture the blossoms around the Tidal Basin.

“I get, every year, to hear the excitement that spring is back — to hear from ex-locals who have moved away and like to follow along from afar for a little taste of home, to hear from visitors planning trips to tick off a longtime bucket-list item,” Mr. Coleman, 50, said. “What really brings it alive for me each spring is the palpable enthusiasm people have for them.”