Tomorrow.io launches two more microwave sounders, S12 and S13, on SpaceX

Fifteen satellites on nine rideshares

Tomorrow.io says every satellite it has flown went up as a rideshare on a SpaceX Falcon 9, sharing the rocket with other spacecraft. With the latest launch, the company counts 15 satellites launched since April 2023 across nine Transporter, Bandwagon and Twilight missions.

The first two, Tomorrow-R1 and R2, flew in 2023 as precipitation radar pathfinders operating from a small satellite. Since August 2024, every launch has carried microwave sounders, which are instruments that read the temperature and moisture of the atmosphere through cloud. The company lists S1 and S2 in August 2024, S3 and S4 in December 2024, and S5 through S9 in 2025. S10 and S11 launched in January 2026, and S12 and S13 followed on October 1.

In July 2025, according to Tomorrow.io, tests in NOAA's Unified Forecast System showed its sounder data improving six-hour temperature and humidity forecasts. The company says this made it the first commercial provider of operationally validated microwave sounder data.

Why revisit time matters

A satellite in low Earth orbit passes over any one place only a few times a day, Tomorrow.io explains, while a storm can form, deepen and reach land between two passes. Revisit is the time a place waits between looks, and it sets how fresh the starting picture of a forecast can be.

In January, the 10th and 11th sounders brought the constellation to a 60-minute global revisit. That is the cadence its Sky 1 system uses to rebuild the global atmospheric picture every hour. The company says its global revisit today runs well below 60 minutes.

Before this launch, eleven Gen-1 microwave sounders were active in low Earth orbit, and S12 and S13 are Gen-1 sounders too. Tomorrow.io says the work has shifted from building the constellation to keeping it fresh, adding satellites so the hourly picture holds as the fleet ages.

DeepSky and the push beyond radar coverage

The next step is DeepSky, which the company describes as its next generation, now being built. Each DeepSky spacecraft will carry five instruments: Gen-2 hyperspectral microwave sounders, GNSS radio occultation, GNSS reflectometry, infrared and visible imaging, and precipitation radar. All five will fly on the same spacecraft at the same time, so they read the same column of atmosphere together.

Tomorrow.io says DeepSky is aimed at places where warning arrives late. It cites that roughly 71 percent of Earth is ocean with virtually no ground-based weather radar, and that more than five billion people live outside radar coverage entirely.

Government and field use

The company points to several outside uses of its data. In June, NOAA's National Environmental Satellite, Data, and Information Service awarded it a contract to provide microwave sounder observations under its Microwave Sounder Data Buy. In September, NASA's Commercial Satellite Data Acquisition program began a formal evaluation of its sounder data.

On the ground, a two-year pilot in Kenya with TomorrowNow.org and One Acre Fund sent Tomorrow.io forecasts by SMS to nearly 10,000 smallholder farmers. According to the company, their yields rose 12% relative to a control group, and with TomorrowNow its forecasts now reach millions of farmers in East Africa.

For users of the data, the launch signals a focus on maintaining the hourly global picture as satellites age, while DeepSky is meant to extend coverage to regions without ground radar.