I am looking for information on climbing Aconcagua in Winter.
1. What is the best time in Winter?
2. What is the weather like?
3. How much snow falls?
4. Sure there will be winter storms, but how frequent and long will the clear spells be?
5. How cold does it get?
6. Are the rivers frozen over?
7. Will the bridges be usable?
8. How bad is the avalanche danger?
9. Will the Berlin hut be usable?
10. Is there enough snow for to use skis and a sled the whole way?
11. Will there be technical climbing on the Normal Route?
12. Will we need rope and pro? If not on the route, how about crossing the rivers?
13. Do we need a permit?
14. Is transportation available from Mendoza?
15. What is the average time for a winter trip?
16. Will there be any other climbers?
17. Is the Polish Glacier feasible in Winter?
18. Do radios work?
19. How good is that ski resort near the trail head?
20. Am I cracked?

Please let me know what you know.
I am also looking for interested team members.

Aconcagua page-at the bottom of the permit section there is this information:
Off –season (from March 16 to November 14) access to the Aconcagua Park is no longer free. A permit must be purchased in Mendoza or at the Park Rangers’ Shelter in Horcones Valley. The price of admittance is the price charged during the high season even if the rescuing service is not provided. Neither doctors nor park rangers are available during this period. However, for a “special” price, there is an exception between March 16 and April 1st., of each season.
To access the Aconcagua Park within these periods, for trekkings or to climb, we suggest contacting the Aconcagua Park’s authorities. There are restrictions regarding the access of MINORS to the Park: they will have to exhibit pertinent authorization signed by both parents and certified by Public Notary or their respective Consulate or Embassy. For further information, please, contact the RENOVABLE NATURAL RESOURCES BUREAU (Dirección de Recursos Naturales Renovables) located in General San Martín Park, phone + 54 261 425 5090 or + 54 261 425 7065 (from 08:00 AM to 01:00 PM) e mail: aconcagua@mendoza.gov.com.ar

At the very bottom of the page there is this information from Boris Krielen.
I have climbed Aconcagua and reached the summit friday 29th of March 2002 during the Viento Blanco, the terrible snowstorm. As I was going to high camp, I was the only one in the park, quite an exclusive experience! After the summit, going down through the fresh snow was pretty cool, though routefinding becomes more difficult and danger of avalanche grows. Routefinding during the Viento Blanco is extremely hard. GPS can be a help. Local brochure has a list of waypoints. I didn't take a GPS. In advance, government people told me by e-mail to pay US$ 200 for the permit and US$ 70 more for several legal services and notary-papers. This turned out to be all nonsense. I paid 40 pesos at the entry of the park. Entering the park in high winter - June/September - might be more difficult though. Government and park officials indeed don't encourage this. Danger of avalanche is huge then.
After 16th of March there are no mules available from Puente del Inca or Punta de Vacas. Mules are not allowed into the park between 16th of March and 15th of November. Outfitters bring the mules down to Mendoza for the wintertime. Therefore I was the mule myself, carrying 32 kilo's. That's the way a real solo-expedition should be like, I think.

There are no wide rivers to pass on the normal route. On route to Plaza Argentina (Polish Glaciar) the river has to be passed at least twice. This could be a problem without mules. Until July, don't count on snowbridges to cross the rivers lower in the valley. Take a towel and light shoes!
Thanks Boris

That is all I know. Perhaps you should contact Boris (I searched for his user name but came up empty). Some things have changed for sure like the permits being the same price as the high season but the conditions will be relatively the same as when he went. You will just get no rescue support as there will be no rangers in the park.

1. What is the best time in Winter?
(Don't know)
2. What is the weather like?
(Cold, snow and storms)
3. How much snow falls?
(Varies from year to year)
4. Sure there will be winter storms, but how frequent and long will the clear spells be?
( In the summer the weather systems seem to last 5 days, on average. This mountain creates its own weather however. Have not been there in the winter to say if this pattern remains constant)
5. How cold does it get?
(Burrrr. it can be -30c in the summer so the winter... I don't know)
6. Are the rivers frozen over?
(Should be)
7. Will the bridges be usable?
(Should be)
8. How bad is the avalanche danger?
(Will depend on the conditions. Plaza des mulas and Camp Canada would be in the line of fire in my mind)
9. Will the Berlin hut be usable?
(The new one should be OK. Will be partly covered with snow probably. The old ones are ruined. Thanks for the update Ario)
10. Is there enough snow for to use skis and a sled the whole way?
(I would imagine so. But each winter would be different. Last year there was record snow)
11. Will there be technical climbing on the Normal Route?
(No)
12. Will we need rope and pro? If not on the route, how about crossing the rivers? (Should be no problem on the normal route, Big issue in the Vacas approach and would avoid this route myself)
13. Do we need a permit?
(YES)
14. Is transportation available from Mendoza?
(as far as the ski resort, Penetentes. The bus usually stops at Puenta del Inca but I am unsure if the hostel is open in the winter. The ski resort is at Penetentes)
15. What is the average time for a winter trip?
(I would guess 16 days)
16. Will there be any other climbers?
(Most likely no)
17. Is the Polish Glacier feasible in Winter?
(I would think it would be avalanche prone, and you would have to approach from the normal route by doing the traverse in reverse)
18. Do radios work?
(Yes, depending on where you are)
19. How good is that ski resort near the trail head?
(3 Star)
20. Am I cracked?
(NO)

9 -
William, since your last visit to the normal route, they (Germans & Argentinians) have constructed a new wood shelter at Berlin, at a spot 50m farther up (+10 m elevation) from the 2 old ones and twice their size. January 2006, it was in good condition / nothing broken.
here is a picture:

Thanks Ario for the update. Great. Cheers William

Icescrew,

A friend of mine, who's organizing trips to Aconcagua showed me a lot of good photos from his friends climb of Aco in mid winter. It looked really interesting with those huge snow fields. From what I remember of the story he told, the only problem they had was the cold. They used skis, but I can't recall how high up on the peak.

Here's the main e-mail address to my friend's company:
info(at)aconcagua-xperience.com.ar
Ask for Eduardo.

I agree on most of what William says.

15. I will make a plan for more than 16 days. You may have to tell the authorities you may overstay your permit before going there. 20 days is not much if the weather turns grim. If you are fully acclimatized before entering the park, 20 days should be enough.

18. Radios works fine, but I have no idea if the rescue team, any rangers etc. will be on stand-by in the winter.
There are no rangers in the park in the winter.

I'm sure you'll have a nice time there.

JC.

Thank you all for the information.

I am familiar with the normal route from several years ago.

One of my concerns is that the Canaleta will be icy and require technical gear. Any thoughts on that?

I figure Plaza de Mulas would be safe from avalanches over towards the Refugio, but if the climb up to Nido de Condores is avalanche prone, is there another route that is less steep? Perhaps further to the left (North)?

I am familiar with the new Berlin hut, but will it be covered in snow and difficult to get into?

I have my work cut out for me.

Cheers.

! Hola companero !
I was told several times that Plaza de Mulas is avalanche prone and that’s why the hotel / refugio has been built that far from the campsite. Haven’t been there at that time of the year though…
In January the Jack-of-all-trades @ Rudi Parra, a guy called Ulises, was talking about him going for a winter attempt this year. I may be able to find his e-mail through a buddy from Aragon...
! Suerte !