No, weather forecasting models are "just math". The forecast itself is an output of the model. I sure hope our weather forecasting models are still useful next year!
weather forecasting models <=> code <=> math
weather forecast <=> program output <=> calculation results
That's why I said "[yesterday's] weather forecast" and not "weather forecast models".
But my larger point actually also stands: Weather forecast models also, in the end, incorporate information about geography, likely temperature conditions etc., and might not be stable over 100 years.
The more interesting question is probably: Is Python more like the weather or a weather forecasting model? :)