Drive it when the roads are clear. Don't worry about the temps. Just drive it. It's far better off driven, when you the the time to warm it up and get the cockpit dried out, too.

 

Can someone explain this quote from the owners manual ("factory tires are unsafe below 40 degrees")? Seems odd since you could be out driving in 50 degree temperatures during the day and then it drops into the 30's on you way home at night.

 

I think it means that the tires are not safe below 40 degrees F. Actually many of the tires will work below that temp, especially if they are already warmed up which is the scenario you suggest. However if the tire is that cold, it becomes very hard (think hockey puck) and loses its flexibility and hence grip. It won't react well to wet/frosty/icy/snowy spots and can't corner in the dry like it can when warm. Thus, they become dangerous.

I generally keep my summer tires on until I see weather forecasts with the temps when I'll be driving (so really the low temps) getting to the mid-30s and the highs below 50F, or until snow is forecast. This year they went on the went on in late November.

Winter tires have their limitations, too (in my case they are 265 rears vs 295 on the summer tires, with obvious grip differences), but I would rather drive the winters at 50F than the summers at 39F. And the winters are cheaper than the summers (maybe because of size?) in fact I looked yesterday and found at Tire Rack replacements for my 4 Michelin Pilot Alpins would be $682 plus shipping. So all-in-all the winter tire is the cheaper and safer tire to be on when it is cool/cold out.

 

One of the best things about Porsche is the fact that they can be reliably driven daily. People who use these as garage queens are crazy. I drive my 09 C2S in winter North East weather daily. Sure, I have my truck for the bad stuff, but if the roads are dry the Porsche is out.

 

try it and you`ll see for yourself. high performance tire compound freezes up and efficiently becomes nice piece of glass with glass traction capabilities.

my ps2 tires did it at 23 degrees appx., it was quite fun. what you do is to break several times to heat them up them it comes back to normal, but there is nice chance to slip and crash into something when you have no proper traction. much wiser way is to mount your winter set of PA2s and ride on them until spring.

 

+1 I just drove my C2 with winter tire package from Tire Rack from NYC to the Hamptons in a moderate snow storm and the car handled beautifully. Admittedly, when a blizzard puts 2' of snow on the ground I'm not going anywhere, but except for such situations I drive all winter long.