Provence or Alsace/Burgundy end of August?

I think either of your areas will provide plenty to do, but I'd keep in mind the risk of very hot weather in both locations, and consider what activities will be most pleasant if you hit a series of 88F - 93F days. I guess being in Alsace puts you in a better position to run for the mountains if you really need a break from the heat. On the other hand, you will be heading for five days in Chamonix...

Both areas are a fantastic visit. Of course Alsace is closer to Chamonix.
Perhaps easier with less driving. Work out the mileage in case that matters to u.
Either location will be very crowded so book your lodging ahead.

JS - would you consider Bugundy (say Semur en axois area towns) and Alasace (Colmar area towns) both doable in this time frame (maybe three days each?) or best to just pick one area before heading to Chamonix?

It's only a little more than 3 hours driving from Semur to Colmar. Both areas are worth seeing, and you can see a lot in 3 days. Or you can shave a day off one of the 2 and stop overnight on the drive. There are some very interesting towns along the way.

I suggest Alsace as Provence might be too hot at this time of the year. At least for me it would be too hot.

In addition to the points made by others about potentially high temperatures in Provence that time of year, that's also nearing the end of the traditional vacation season when French families from points north of Provence head south to the coast and to family vacation houses in southern France.

Consequently roads can be jammed with Parisians, Lyonnais, and others in, and on the roads leading into an out of, Provence.

I would much prefer to be Alsace in August rather than southern France.

If you look at the prediction of traffic in 2018 based on historical observations (http://www.bison-fute.gouv.fr/IMG/pdf/17237_Calendrier_Bison-Fute_2018_Web.pdf), you can see that Aug 24-26 is expected to be "difficult" traffic, with traffic in the Auvergne-Rhône-Alpes region (which would be on a likely path between Provence and Chamonix) anticipated to be "very difficult" on 25 August.

As you head to Chamonix, if you go by Montreaux on the east end of Lac Léman (Lake Geneva), don't forget to play Deep Purple's Smoke on the Water on the car stereo in commemoration of the fire.

Hi all,
back again with a final update and in search of your expert opinion...
we have decided to make Alsace our middle section of trip and then drive from Alsace to chamonix in one day. I lean taking the Swiss route via Basel east of lake Geneva with perhaps a rest stop to see chateau de chillon before finishing the drive to chamonix via martigny.
does this seem like a reasonable days worth of travel? Drive time looks to be about four hours, not including stops.

Bob has made an excellent point in drawing attention to the summer vacationers going here and there. Check the Bison Futé site for your date. If it's an orange or red (or even worse, black) day, the four hours will turn into many more.