The brief

Analyst view

• Bets that AI weather needs its own data: 600+ balloons aloft at once, sampling skies over oceans that few sensors reach.
• WeatherMesh-6 (June 2026) claims up to 38% lower error than ECMWF's flagship model; independent checks are pending.
• Raised a $37M Series B in Aug 2026 (Khosla, Galvanize); over $62M in total.

Technical approach

As reported

Balloons

Weeks aloft, steering by altitude

A few pounds, mostly sand ballast. Rising or sinking into different winds steers it; one flight gives about 50 profiles vs 1 for a normal balloon.

Coverage

Data where there was none

Balloons cross oceans and remote regions where weather stations and normal balloons are scarce, the gaps that limit global forecasts.

Forecasts

WeatherMesh deep-learning models

Its AI models are trained on public weather records and fed its own balloon data at forecast time.