I'm in Wisconsin. Other than the three days of 40's we had last week, it's been damn cold for about a month. The TB is my wife's DD so it does do quite a few short trips. She drives 3-4 miles each way to work each day, but it does do quite a few long trips too.
I can't really say how long it takes to accumulate. I'll have to admit, the oil change I did today was quite a bit overdue (7 months and 8,300 miles, but before the oil life monitor said it was time for a change). I'll have to keep an eye on it. I've seen this goop before, but I've never correlated it to cold weather. It's not there all the time. Maybe it's only showing up in the winter. It did throw a P0014 code twice about a week ago. I cleared it with my Torque app and it didn't come back. From searching this forum, sounds like those can come from dirty oil (which is why I got off my a** and did the oil change despite the fact that it was 5 degrees out).
I'll report if it keeps coming back while it's cold or if it goes away if it warms up (if it ever warms up).
Just put new tires on the TB so I'm signed up with this thing for another five years!