IF the career weekends are structured the same as GP weekends, with just the added part of not giving the user control of the settings. It might be possible to change both weather and time internally, but its easier said than done, as I first would need to find where those values are hidden. And it can be very frustrating process when you go in blind not knowing what each value is.
So far I've been trying to dissect the weekend structure, and have only really found P/Q/R values. As I wanted to see if could change which weekends are sprints. But it gets bit complicated than just changing the inner weekend values, as they get overridden which I'm assuming is the 'outer' season manager that manages the weekends. So I need to hack up something to pull a uno no U on it to maybe make custom sprints work, and I wouldn't be surprised if the Time and Weather settings are hidden somewhere near the season manager as well ... but again no promises, its a complicated process, at least for me.
Its always hard to say, like technically the game obviously has those values for drivers and their teams loaded in memory somewhere for it to display it to you, obviously. The tricky part as with anything cheat engine, is figuring out where those values hide, and it becomes especially tricky when they dynamically jump all over the memory... so idk, maybe ? I know someone was messing with driver stuff in CE, but I'm unsure how far they got...