As you know, you can't predict the weather. Maybe you hit an unseasonable spell. I've been in Southern Puglia for a week where it's freezing, snow, ice, schools closed the last time this happened was 20 years ago. Now I'm in the middle of Basilicata where it's always supposed to be warm, but the temperature is 0 today. Next, I'm heading to Naples, where it is also barely above zero, and dusted with snow. Most places down here don't have the heaters for it. You make do. It's not home. By being at Lake Como, you had it way better than most if there was a heat wave. Any crowds were probably Milanese desperate to escape the heat and get to much cooler Varenna, Mennagio, etc.

Even if you go up to the Dolomite mountains and stay in Bolzano, which every year for years and years wins first place as the best city in Italy, despite the mountain location the high is in the low 80's but can be higher on any given day.

Remembering, that region, Trentino Alto Adige was taken as a war prize from Germany after World War 1. Students from there come to Venice to learn Italian because they still speak a lot of German. They even refuse to say they live in Trentino Alto Adige. They all sY they are from South Tyrollean Mountains, or Sud Tirol. You can stay cooler but not cool there.

I mentioned Piedmont because you said the trip would include France. Piedmont, like Sud Tirol, is a mountainous place. In fact, the 2004 Winter Olympics where held there. In the summer it's cooler than most. You don't have to go all the way over to Germany. They have great towns, the best wineries, the best food, some of the best scenery, and non-touristy prices. You can always spend a day in Torino, the fourth largest city that unlike Rome, Milan, and Naples, is purely Italian, untouched by tourism.

A couple of years ago when I was working in Torino I told another professor that there is no tourism in Torino. She told me, "You better not let the Mayor here you say that because it's what he's been struggling to make happen for years."

Whereas Austria is right over the Dolomites from Trentino, France is right over the Alps from Piemonte.

Just forget about heat waves. They're like terrorism and tornadoes. In 2013 over 15,000 people died of the heat wave in France. People in Switzerland and Germany were dying of heat. The French morgue didn't have enough places to put people. Most of these people lived where there was no air conditioning, or else it wouldn't have happened.

Italy was more or less spared, because it has frequent rain showers in most parts. People around Lake Como, or anywhere in the Lake Country are blessed. They just get in the Lake.

I personally, have a hard time in New Orleans because of the humidity. I'm always sticky and wet, like the people in Milan. Not at Lake Como. I think it's a matter of expectations. You don't go to Italy, or Europe for that matter to cool off.

You also always need air conditioning because of the curse left to Italy for all its fine weather: mosquitoes are almost everywhere, most parts of the year north, south, east, west, except in late fall, winter, early spring.