We were out there as well. Good times sleeping under a tarp in the rain witha wet foot box:P
Not the first time this has happened to me. About 10 years ago we got rained on going in and it fell to -17 that night.
Needless to say I bought a hot tent right after that trip (though I still sleep outside it is nice to have aplace to hang out and dry out your clothes during the day/evening).
I ALWAYS STRESS to the winter camping newbies: It is essential to bring a very good (i.e marmot preclip) rain jacket and pants to use as an out shell. Prefer light weight. They always want to bring snow pants (which are horrible for layering....I prefer rain pants that can be opened up along the sides via zipper to cool off).