Weather forecasting is a non-starter application for quantum computers. It’s a chaotic system. Quantum computers cannot handle chaotic systems.
In addition, you have to be very specific about what you are asking the QC you do. What would you ask it? “Will it rain” ? Good luck coming up with a QC algorithm for that. Actually, don’t bother - it won’t work (see “chaotic system” above)
Why does weather forecasting keep being peddled out as a likely application for QC?