Scott Patterson wrote:are any of the ranges climbable in december?
Apparently the only places in Peru that are reasonable then are the parts around the Atacama such as the Arequipa region.
I've been to South America (Peru, Bolivia, Argentina, Chile) from between Dec to Jan for the last three years, including those places that you mentioned, and you're right that the weather around Arequipa and the Atacama near Chile is pretty good in December but it also becomes rainy towards the end of the month.
I just returned a few weeks ago from Peru where I was hoping to acclimitize on a climb near Arequipa and then head over to the Cordillera Real in Bolivia to do some more interesting climbing. Unfortunately, I hit the last day of decent weather on my acclimitization climb/hike (snowed heavily while I was on the summit), and my entire time in Bolivia, it rained and/or hailed for a few hours every day, nixing my "real" climbing plans.
If you can head to Arequipa in early December, I think you can get quite a bit of climbing done. Same for the Atacama Desert area bordering Bolivia and Chile (was there last year for a week in mid December). I talked to the locals in La Paz in Bolivia and it apparently starts raining there regularly from November. I haven't been to the Cordillera Blanca and Huayhuash area yet but I'm intending to visit this May/June.
In my earlier reply, I forgot to mention Patagonia. The main climbing season is Nov/Dec/Jan so that's certainly a climbable range during that period. When I was there last December, the weather ranged from hailing/raining/snowing/windy to 3 days of perfect blue skies with sweltering heat so I suppose the weather is as much of a crap shoot as the other ranges.