I've driven it on mornings when it's been in the 20s and 30s outside.
You just drive sensibly. The car will tell you what it can and can't do. Gentle, smooth inputs.
What's really funny is, I still had to turn on the A/C when it was that cold out, after about 10 minutes of driving!
I drive mine all the time in the winter if the roads are dry.
Seven years four different Vipers. Never a single problem.
If you're not capable of adjusting your driving style for cold conditions by all means stay home.
In the cold you drive like you have a hot coffee on your lap, smooth and slower.
Maybe not as much fun, but it beats sitting on the couch looking at the garage.
on the 2nd day of owning the ACR I did about 100 miles in 46degrees and quickly falling temps, it was about 40 when I parked it for the night. did some autocross in mid-40s the day after on a wet track. They don't work very well but they are still tires. I drove a Porsche on Pilot Sport cups in near freezing temps before, so I knew what to expect. btw, it seems that Viper version of cup tire is not as good at channeling water away as the porsche spec one, and the sidewall seems stiffer (which is not great for cold/wet driving)
I bought a second set of wheels and a set of tires with more streetable compount/tread configuration since then, so I can track the car in the winter at speed or drive around comfortably if I feel like it. I drove my previous fun car (z06 corvette) on Michelin PS2s all year around, including (light) snow/slush.
What ViperJon said about adjusting your driving style for conditions is spot on, esp. about being smooth, another important part is to think ahead, plan ahead, and anticipate - i.e. following distances, not pulling out in front of fast traffic so you can accelerate at your own pace, don't brake or downshift if you don't need to etc
Be careful out there.
In addition to the tires having less grip, the engine will make even more power with all that dense cool air.
This means quicker throttle response combined with far less traction.
Driving on snow or ice is next to impossible with these super wide slick tires.
Even with fully treaded tires Vipers do not like the snow.
Take your chewing gum and run it under cold water for a few mins. It will get harder, put it out in the sun it will melt. Same theory with tires. Unless running winter tires of course. I'd say with ps2s anywhere under 60 they will start breaking loose alot earlier, thanks giving night it was spinning some in second gear at about 70mph and it was about 55 out. Had the cups out the other day it was 48 and they was also very easy spin. I would not hammer down by any means at those temps unless in 3rd or 4th gear and again only with front wheels straight and paying attention for wheel spin, go out with no traffic in a straight line and try them. Will see a massive diffence between grip at 80 degrees and 50 degrees.