What temperatures may we expect in Aconcagua?

It is not possible to ensure the temperature in advance on Aconcagua, due to it varies according to weather conditions.

During December and January, we may have -10ºC (-14ºF) at night, and 10-15ºC (50ºF)at midday on the base camp, if good weather. The temperature above 5000m can be 0ºC at noon, and maybe -20°C (-4ºF) or even -25ºC (-13ºF) during the night on the last high altitude camp 6000m. On the summit, the temperature can be -17°C (1ºF) approx and may vary rapidly. All these are just estimated values. During November and February, we may find an average of 5º less approx. 

Although it is often not strictly necessary, we always recommend a -30ºC (-22ºF) sleeping bag. We have to be prepared for all the conditions, that is why we will check all your equipment in Mendoza before starting.

One crucial point to take in mind is that here we have more than 90% sunny days, very hot sun, it helps to feel very good and enjoy every day on the mountain. 

Please find more info at https://aconcaguaexpeditions.com/ingles/5/mtaconcaguaweather.htm