My parents and I are headed to Europe in December. We will start out in London and end the trip in Milan. My original idea was to buy a EU Rail pass and ride the train throughout, BUT my mother wants to visit parts of Austria which its only convenient with a car. Generally speaking, how much does it snow in Germany and Austria in December?

In Germany normally not much thanks to climate change, but the weather is obviously unpredictable. Just 10 minutes of snowfall while you're on the Autobahn (the German highway) can be fatal, if you only have summer tires on your car. Also keep in mind that even though Germany might look small from a US perspective, the terrain is very diverse. So if you drive from London to the Austrian border, you will at least cross a few hilly areas (Siebengebirge, Westerwald, Taunus, Spessart and the Voralpenland) where snowfall may occur while it would just rain in lower-lying regions. As for Austria, most of the country is very hilly or even mountaineous.

Bottom-line: Be prepared and request winter tyres on your rental car. Depending on where you go in Austria, skid chains might be necessary as well.

Don't rely on Deutsche Bahn.

That bad huh?

Thanks! I'll be picking up the car from Cologne Airport. Do rental car agencies rent out chains in Europe?

(at least) Hertz is offering chains (at quite a price..)*).
Note that winter tyres ("M+S") are required in winter conditions (fine starts at 60EUR), also some streets (esp. in AT) might require chains.

*) https://www.hertz.com/rentacar/reser...D=SKI&EOAG=MUC
Noticing one cannot book this service via Internet (ridiculous).

Deutsche Bahn is more than ok, especially if you compare it to US American train companies.

As for skid chains and winter tyres: Major European operators such as Sixt, Europcar or Avis should rent out winter tyres and chains. When in doubt, just call the rental agency. Everybody speaks English nowadays.

Take the train and rent in Austria. Cars in Austria and Germany have to have the right tires anyway by law, so rental companies in these two countries will switch their fleet in October. Trains are fine and more reliable than highways in Winter.

I'd take the train as far as you can and then rent when you get to Austria. Far less stress, even if DB isn't particularly reliable. Rental car companies usually start swapping out to fleets with M&S or winter tires beginning in mid-Sept.

Absolutely, Deutsche Bahn, SNCF, �BB, etc. are fantastic compared to Amtrak.

Prices are very reasonable, too, if you book at least a couple of weeks in advance (and, ideally, make use of promos). My impression is that prices in the UK are a bit higher than in Continental Europe. The BritRail Euro flexi passes are reasonably priced, though.

One-way rentals, OTOH, can be quite expensive. Maybe your parents can limit driving to Austria?

Also, public transportation options in Austria are good. In areas which cannot be reached by train, there is usually a good bus network both at the local level as well as at the regional level (operated by providers such as Postbus). Again, busses usually run at higher frequencies than what you might be used to from the US (whether we're talking Greyhound/Megabus/etc. or the local transportation authority).

I would stick to your current plan. Rent the car in Koln. It will have winter tires and may have chains. All cars in Italy must have chains.
One way rental from Germany to Italy can be very expensive.
Trains are fine if you want to be on the tourist path.
You need a car to get off the beaten path, which from Koln to Italy is so very beautiful and interesting. Stop and stay in small to medium sized towns and you won't be disappointed. People are warm and prices reasonable.
For one way rentals,check out Kemwel.com

In December it mostly rain, but at higher elevations there can be ice and snow. Oh, I see you are from SoCal.
But it's for you mother, do whatever she says. I can guarantee you that in the future you won't regret it. And she is right about Europe in general and Austria in particular, you do need a car.
I go every year, mid-Dec to mid Jan.

Good luck

We've been to Germany and Austria several times in the winter and travelled both by train and rental car.
Generally:

• A car is a good idea in small towns and for local travel
• A car is not necessary and can be a hassle in larger cities
• Rental cars will have winter tires that are pretty effective in most conditions. I've never had to use chains.
• Yes, it snows in the winter, particularly in and around the Alps, which can affect driving conditions. My experience is that the Germans and Austrian are pretty good at clearing the main roads after a snow fall, but parking lots and backroads might not be cleared as quickly
• Trains work well for travel between towns/cities. We often use travel by train for day trips to another town even when we have a car, especially when the weather is bad. One of my favorite trips was from Garmisch to Mittenwald during a heavy snowfall - picture postcard views as we explored Mittenwald without having to worry about parking or driving in bad weather. Get the "Lander-ticket" for travel within a German state.