Would Vienna be overrun by tourists in August? I assume so, but am wondering how bad it would be. I hate waiting in line and crowds, especially in August heat and humidity. I understand that a lot of the locals will be away on their holidays and that somehow seems to make a visit at that time less appealing.

This would be 11 full days, arriving the 9th and departing the 21st of August. The average high temp of 80F would be ok. But I would hate it if there were too many tourists.

The only reason I am considering this is because there is an inexpensive business class fare to Geneva. I don't really want to go to Geneva but there is no option. I do want to visit Vienna and Budapest. I was also considering flying to Stockholm/Copenhagen or train to Milan.

I have booked the flights to/from Geneva twice and cancelled both times within 24 hours for a refund. It is "only" $2340 roundtrip in biz class on SWISS from LAX via Zurich to GVA. That is an almost too good to be true fare these days. Am concerned that the catch is crowds of tourists in Europe in August.

If Vencie in August is the hell, Vienna is not even the purgatory. Places like Schoenbrunn, Hofburg, Prater and Grinzing may be crowded. All other places will look rather normal.
But how will you move from GVA to VIE? Neither direct flights nor beds in the overnight train will be particularly cheap in August.

The last time I was in Vienna was 2014, and it was absolutely packed inside the Ringstrasse. And that was late October, not even high season. Budapest was pretty crowded last time I was there, too. I think it's the river cruisers. I would head north - can you take the Hurtigruten cruise up the Norwegian coast? I am emphatically not a cruiser, but I really enjoyed that.

Thanks for the replies. Ok, it would be packed but not purgatory.

GVA->VIE would be a nonstop flight on the 10th, the day after arrival at GVA from LAX. That was the only date that I could get the nonstop for only 8K award miles. Return on the 17th from BUD or VIE to ZRH, overnight in Zurich, and then train to Geneva. Am holding on to all three award tix because I can cancel for a refund.

I considered the cruise only because the boat would have a capacity limit. Interesting idea but not for me.

Am not a Europe traveler but understand that the locals take long vacations in August. What is the impact of that? Or how is it different in August vs non-summer times? There would still be workers in restaurants, hotels, tourist sites, I assume, but are they fully staffed? Waiting in line because of too many tourists is one thing but combining that with a staffing shortage would seem to just make it worse.

Don't worry! Everything will be open in Geneva or Vienna. Holiday closures take place at non touristic places only.
BTW: Vienna has tons of restaurants, not only those popular with tourists from America or Asia.

United decided it for me. That $2341 fare went up $200 yesterday and today it is $3968. Three years ago I had a ticket on SWISS at the same $2300 price and was looking forward to the flights. This would have been a sort of replacement for that covid cancelled trip. But the 2020 ticket was to Graz and return from Vienna - places I wanted to visit, not Geneva.

Might try the Zipair lie-flats to Tokyo in October instead. That would be a destination and time that I would be happy to travel.