I am thinking of heading over to climb Aconcagua shortly (in Santiago now). The high season starts Dec 15, after which you have to pay 1500 pesos. My question is that if I buy my permit for say Dec 10 to Dec 30, spanning both the mid season and high season, would I have to pay the high season price or the mid season price?

The price has gone up meanwhile, it's now 1800 pesos for high season and 1200 pesos for mid-season, see http://www.aconcagua.mendoza.gov.ar/.

I think if you enter during mid-season, you have to pay the lower price. Last season (2008/2009) I entered in high season and exited in mid-season, and payed for high season. One guiding company on the web who offers a trip entering in mid-season and exiting in high season, says that for such a trip the clients would have to pay a mid-season permit.

it starts from the day you enter the park you then have 20 days. so if you start before Dec 1ste you pay the lo season rate. If you enter before dec 15 you pay the mid season price. you just have to be out within 20 days. I am in Mandoza now and can confirm this 100 percent. good luck and cheers

Wow, 1800 pesos. It's gone up a bunch since I was there in January 2007. We paid 1000 pesos, with a 3:1 exchange rate, so US$333. Now, 1800 pesos is about US$472, at the approximate 3.81:1 rate.

Leaving tomorrow for Aconcagua.... CANT WAIT!