When is the best time of year to go to Aconcagua? Summit attempts are permitted from mid-November until the last days of February, due to the extremely harsh weather conditions such as low temperature and intense snowfalls starting in autumn until early spring. The trekking permits to enter the park (to the base camps only) are given until Easter. The High Season in the Park starts in mid-December and lasts until the end of January. During this period of time, the amount of mountaineers increases as a result of more stable weather conditions, increasing the possibilities of success on reaching the summit. AMG will assist you in obtaining the necessary permits to enter the Park.