To that eternal question “How’s the weather over there?’’ a Boston startup can give you an answer — literally, block by block.

ClimaCell is marketing a hyperlocal service that can detect changes in weather conditions in a tiny area, giving users a better understanding of what they can expect in the immediate future. Combining traditional weather tools with an unusual use of wireless technology, the company can burrow down and show conditions at street level.

ClimaCell has access to wireless signals bouncing around the outdoors, and it monitors those transmissions for disruptions caused by water droplets. It then translates the intensity of those disturbances into a heat map that indicates how much rain or snow is falling on one side of town versus the other, and what it expects to happen by the minute over the next few hours.

Chief executive Shimon Elkabetz said such detailed maps and short-term forecasts are valuable in fields such as logistics, construction, and travel, where even small differences in weather conditions can have a big effect on safety, timing, and economics.

“If you want to know whether in two days from now it’s going to be a bit rainy in Boston or not, the notice is good, but what happens on the real-time basis? Sometimes you look on your phone and it says it’s rainy, and you look outside and it’s not — or the opposite,’’ Elkabetz said.

Elkabetz, a former officer in the Israeli Air Force, and some colleagues conceived the idea while in the military, he said, after seeing how undetected or misread weather conditions could decide the success or failure of a mission.

On Monday, the year-old ClimaCell announced it had raised $15 million in new venture funding, led by the Silicon Valley firm Canaan Partners. It now has raised nearly $20 million since sprouting from the Harvard Innovation Lab, with seed money from Ratan Naval Tata of the Tata business conglomerate.

“By shifting from forecasting to more accurate, granular, real-time predictions . . . ClimaCell is changing the way massive industries assess, manage and make decisions around weather risk,’’ Rich Boyle, a Canaan general partner who is joining ClimaCell’s board, said in a prepared statement.

The company said it already has clients in fields such as professional sports, air travel, shipping, and finance, though it declined to disclose information about its financial performance.

ClimaCell is one of several firms trying to change the business of weather, which has long leaned heavily on observations collected by massive, costly government satellites and doppler systems that scan skies. Some competitors are raising money to launch their own small satellites to provide specialized observations, for instance.

And others, including established technology companies and major players in the weather information business, are working on ways to provide more granular data.

Nancy Colleton, president of the Institute for Global Environmental Strategies, which works on outreach and education around observations of Earth, said ClimaCell is making a smart move by focusing on the industries that can use its services.

If the company can surmount the challenges of monitoring areas with little wireless activity and data coverage to provide reliable information everywhere, she said she believes the company has big potential.

“Everybody’s looking for this data, and it’s going to come down to who can get it to me in the form that it is most useful to me and at the time that I need it,’’ she said.

Andy Rosen can be reached at andrew.rosen@globe.com. Follow him on Twitter at @andyrosen.