It has been proven many times in the state of California that McDonald's food containers simply cannot be constrained within the confines of an automobile once the food has been consumed." roads are clear but damp, and have a little salt on them"
There's only one correct answer to this and it's the speed limit. It does not matter the car since we really don't have roads over 70 or 75 mph and the vast majority of cars out there will handle that just fine. Why would temp have anything to do with anything? If the roads are clear but damp with salt, then speed limit it is maybe 5-10 over depending on the scene. Of course we'll always take precautions around sharp turns etc..
Another pet peeve I have about rain is why on earth would every state not have a 'Headlights on" law when it's raining? It's so simple and actually one of the good laws. Some states have it and some don't. What all states don't have though is someone telling cigarette smokers to stop throwing out their butts out the car window. It's as if they think they are so small that they're really not trash or littering. I assume they would not throw their McDonald's bag out the window so why the cigarette?