Please advise if renting a car from Athens and driving to Meteora and Delphi is doable - in JANUARY. Can we count on good (as in non-snowy) roads? Plan would be to spend 2 nights in Meteora, 1 night in Delphi on the way back, 3 or 4 nights in Athens. Are there any day trips out of Athens not to miss? I remember going to the Temple of Poseidon somewhere out of Athens (in 1970!) - I'd like my husband and son to see the spectacular view from there too. Thanks for all suggestions.

I think the Temple of Poseidon you are thinking of is at Sounion, south of Athens - about an hour+ drive.

The winter is a bit of a crap shoot - most of the time the roads should be fine, but if there's a snow storm then it could take a while to clear the roads. There's a ski resort near Delphi, so they do get snow, especially in later Jan/early Feb. If you're skiers it's kind of a cool thing to do since most people don't realize that you can ski in Greece. I've driven further north (Ionnana/Katara Pass) around Christmas and barely made it with chains - but that's unusual. In the mountains they do sell chains at all the gas stations/small shops if it does snow.

Naufplion is a great trip from Athens - it's about 2 hrs and there are buses all the time if you don't want to deal with a car. You could spend the night if you wanted to.

Another place that's quite picturesque is Monemvasia which is way south on the Peloponesus peninsula - best way to get there is via ferry/Flying Dolphin hydrofoil, but I don't know if they run in the winter. It's about a 4-5 hr drive otherwise and you could make a detour to Naufplion on the way.

We got caught after Christmas in the Katara Pass and it was a scary thing. Started clear and turned into snow and ice and they closed the pass but we were in it. Didn't have chains on the rental and fortunately a truck behind us sold us a spare and put them on for us. Drank a lot that evening.

You can take a train/bus to Meteora from Athens and once there, hire a taxi to be your guide to go to the monestaries.

Meteora is a DO NOT MISS! (IMO).

Delphi is at the foot of Mt Parnassos, and further up the mountain, at the 2,000 meter level, is the ski resort. They are skiing there right now, and you can view the activity during Greek daylight hours at http://www.snowreport.gr/snowcam/parnassos/kelaria.html

Normally roads will be fine at lower elevations. Just check the weather reports before setting out from Athens.

you will spend lots more on the rental, but one winter trip I was glad we had rented a 4 x4 Jeep from Hertz..it was bad on gas, but great on the snowy passes..also FYI the hydrofoil to Monemvassia has not run in a few years..I would suggest, as much as I dislike group tours, that for this season, Delphi and Meteora can be done on a motorcoach tour. Driving the mountains with snow and ice on the road is far more treacherous than here in the Northeastern US, were we are ready for snow, as are our highway departments..we found the Greek snow removal method to be more "maybe it will melt" rather than seeing lots of plows on the road. January is a great time to visit Meteora, as the monestaries provide shelter (albeit very slippery windy climb to get to them), but in a snow storm Delphi would be a bust, as it is a large outdoor site, with a small but wonderful museum.
I might consider Southern Greece a safer bet for winter travel (but note they can get snow too!)

Many people keep saying Delphi can get snow in winter and trip is not a safe bet etc. I would rather say that there is a 99.9% possibility of not meeting any snow at all on the way from Athens to Delphi and vias versa and a 0.01 % possibility of snow.
Ski center was open for skiing till 3 days ago, now only it's cafe/restaurant is open for visitors,as there isn't enough snow. Yes, on January there are always some good snow falls up there, but that's up there and not down here ( I am writing this been in Delphi, that's where I come from,so I know what I am talking about). Even if there is a light snow fall, roads will be cleaned and fine.
Now, some ice on the road due to very low temperatures is more possible in an extremely cold morning, but again there is only a 1-2 % possibility for a so cold morning in Delphi. Even Arahova the "in" winter destination who is 10 minutes drive away from Delphi and 500 meters higher, rarely sees snow inside the town.
If you can do this trip on a car hire, do it! More flexibility, and you can add some sort side trips such as a visit to Galaxidi (charmy sea-side town 40 minutes away),Arahova on your way here or back, and if times allows, a detour inside Livadia town to see the Krua=small water falls and mills and an ancient site further up.
So go ahead and count on a Delphi trip, unless you are extremely unlucky! -No need to prebook far in advance anyway.You can do that when in Athens-