In reply to pec:
> ... it would be worthwhile waiting to see if its an El Nino year as that tends to play havoc with the weather. I think you normally know by early new year but it would be worth doing a bit of research on it.
I think this should be the main overriding factor in whether to go to the Peruvian or Bolivian Andes in any year. It can ruin a whole season.
They called an El Nino for this year, but a fairly late one - not hitting until July or so. But I don't know that it really eventuated. It causes havoc here in Australia too - severe drought conditions, as in California - so everyone watches it here. It seems it might only be starting up now, so it could be over by next Andean season.
You really need to check with someone in-country to see how much snow is/has fallen around March-April or so, which will give an indication of snow/ice coverage on the mountains. A dry rainy season (as in a La Nina) followed by a dry summer means everything is bare and falling apart for climbing. A bad El Nino means too much snowfall and rain during the season. You can always get something done, but it's far from ideal.
People usually climb earlier in the season in the Huayhuash, like late May to early July, but it's always a gamble.