Professor Falconi certainly does a great job recommending what to bring, but I would like to emphasize certain things that I have learned from travelling around Peru.
If you are like me and are not good at dealing with the cold, I recommend preparing for a Nashville-type winter in Cuzco. Some students got away with only having a few layers, but Cuzco’s altitude adds an extra, indescribable layer of cold that needs to be dealt with. Cuzco winters also include some occasion drizzles that require some sort of rain jacket. Remember you can always buy indigenous sweaters (chompas) but these do not repel water well. The temperature ranges from the low forties in the mornings and night to the mid-fifties during the day when the sun comes out.
The difference between standing in the sun or in the shade on weekend hikes (or if they sun is hidden behind the clouds) is anywhere between a 5 to a 15-degree temperature switch. This is why the title of this blog post emphasizes the need for layers, if you don’t want to be sweating at one moment and then freezing another. Finally, bring a pair of hiking shoes, not the ones that provide ankle support, but the ones that can double as regular shoes during the day. The hike down to Pisac certainly requires a lot of grip and support in order not to slip, so any pair of hiking shoes will do.
Many of the weekend hotels that we stayed in did not have heating as well, so the sleeping bag liner is very useful some nights as are a heavy jacket of some sort. Sunblock is equally as important, as most of this year’s students burned quite easily on our hikes; the sun at higher altitudes is much more strong than usual. Sunglasses and a protective cap of some sort (tennis/baseball cap or a bucket hat) are ideal.
The difference in weather and temperatures between Cuzco and Lima is extremely different. Lima is a coastal desert, and thus does not experience the winter that Cuzco experiences in the higher altitudes. Expect mid to high sixties to lower seventies for Lima; this certainly constitutes shorts weather, with a windbreaker for night time when the temperature drops by 10 degrees.
Since the majority of the trip is in Cuzco, I recommend packing primarily for the colder weather, and bringing a few pairs of shorts for Lima. Also bring a bathing suit or a dry-fit outfit for the white-water rafting/beach for the last weekend.