Isn’t it winter down there? Guess you didn’t know that.
Does it snow in La Paz Bolivia? Of course it doesn't snow often in La Paz, and even in “winter,” from June through September daytime temperatures typically reach into the upper 50s during the day, and fall to the low 40s at night. It seldom ever freezes in this high mountain region, and winters tend to be the dry season.
I've been to 49 states, 48 countries, and 47 national parks. Suggestions:
National parks: top three are wows: Yosemite, Yellowstone, and Grand Canyon. Lots of other great choices: Redwoods, Olympic, Zion, Crater Lake, etc.
Great US cities for museums, food, and history: Washington, DC; NYC; Boston
Great international cities: London, Paris, and Rome have so much! Lots of other great cities as well, depending on what you're looking for. Lots to see and do in Istanbul, Vienna, and Amsterdam.
Off the beaten path: Cracow (not bombed out in WW2; visit Auschwitz; Schindler's List factory; world heritage salt mine at Wieliczka; affordable!)
Machu Picchu is the most stunning place I've visited (visually, architecturally, historically).
Tropical paradise: Virgin Islands
Natural beauty: Croatia, New Zealand
Lots of other great options, but if you haven't done some of the "biggies," they are worth the visit.
I'd also recommend staying in a place and getting to know it in more depth. I led a trip to Boston, and we did a number of days with different themes for 12 days: historical Boston; literary Boston; education Boston; political Boston; fine arts/museums Boston; food Boston; natural history Boston; ethnic Boston; sports Boston, etc.
Norway, specifically the Lofoten Islands. Unbelievable scenery, there are cool places to stay, lots of hiking and outdoor activities, and if you start to run low in terms of budget, you can camp (almost) anywhere in Norway.