I didn't think you were taking me to task, there are many ways to do this but inclement weather is always dicey at best. Assuming that the Op is new to long distance riding I tend to include cautions along with some means of mitigating complicating factors.
My scariest moments have almost always been in the rain for reasons ranging from water being thrown on me by other drivers maybe as they pass me, lack of visibility for me and the driver, (even when using Rain-X), hydroplaning, etc. In snow most drivers tend to slow down and will often give me a fair bit of room but rain, well, all bets are off. If you couple that with feeling rushed to make certain distance/time targets it can be a recipe for disaster for new riders and long experienced.
I guess, at the end of it all, we all our own systems and levels of risk acceptance. Just be aware that long distance riding can be exhausting physically and mentally. It takes a toll when the conditions are good and you've been at it for 20 hours. If you mix in inclement weather bad things can happen and, in that impaired state it can be difficult to make good decisions, especially if you're close to your goal.
Wow, I'm not known for counseling caution! It must be that maturity that creeps up as you approach 50!