The weather in Cusco is generally mild, although it is not like anything I’ve experienced in the US or Europe. There are no Florida hot summers or Wisconsin frozen-car-battery winters. In Cusco you only have 2 seasons: dry season from April-November and rainseason the rest of the year.
During rainseason in Cusco it rains for a few hours every other day or so, but typically the rains aren’t heavy downpours. Since it is summer in the Southern hemisphere, temperatures are mild except during and right after the rains.
The mountainous terrain and generally lousy building codes / civil engineering here make for a wet and dirty city during rainseason:
Worship the sun
Visit Cusco and you’ll understand why the Incas worshipped the sun: since the city is at an elevation of 3,400 meters (11,000 feet) there is little protection from the sun. During periods of sunshine the temperatures are mild but us gringos need hats, sunglasses and sunscreen to keep from getting a severe sunburn.
As soon as the sun goes down, it gets colder than the proverbial witch’s boob – or wizzard’s balls for the emancipated crowd. The coldest months are May – June, when the days are shortest here in the Southern hemisphere. Since there is no heat in most houses, when it is cold outside it’s also cold inside. It’s not unusual to wear a scarf inside the house, as I am right now.
What to bring:
If you’re planning to visit Cusco, bring some light clothes to wear when it’s sunny and a warm jacket for nighttime. Hundreds of vendors will try to sell you chalinas (alpaca scarfs), chullos (typical Peruvian hats) and sweaters, so you can get those here instead of bringing them in your luggage.