I'm trying to get a sense of what type of weather to expect in Lima, Cuzco, the Sacred Valley and Machu Picchu this time of year. From what I can tell (and for some reason foreign weather forecasts are often inaccurate on the web), Lima has highs near 70 F and lows around 60. Cuzco's highs seems to be only a few degrees cooler, but they get cold nights -- into the 30s.

It seems like the Sacred Valley and Machu Picchu are a bit warmer (lower elevation) that Cuzco.

Are these reasonable expectations? If so, it would seem there's no reason to bring shorts and that even short-sleeve shirts are dubious. And I guess a couple of light layers would make sense for Cuzco's temperature swings. Correct?

Thanks for the packing help!