Blue Danube cruise in early October - clothes

All are fine. Jackets not "required." many wore them aboard ship anyway. Even more wore them to the welcome dinner at Lobkowicz Palace at Prague Castle, to the special dinner at Palais Pallavicini in Vienna and the farewell dinner at the Akademia Club in the Hungarian Academy of Sciences. I did the optional 43 km (26 mi.) bike ride from Engelhartszel to Aschach (eastbound Blue Danube)- my wife rode the ship- the bike trail along the Danube is flat and excellent, mostly asphalt. I wore jeans but anything, including biker spandex , is ok. I was 69; I swim and walk a bit, but am not much into biking so I trained a bit starting a few months before, until I could do 26 mi. in one, non-stop ride. The actual ride was easier, but still a bit of a challenge. We we had stops and had to take two small ferries so there were chances to rest and I didn't need oxygen, epi, or an ambulance at the end . Two ibuprofen and I was fine for the next day's activities. My wife did the much shorter bike ride from Dürnstein to Weißenkirchen in der Wachau and back. You might need something a bit warmer than a wind breaker- maybe a fleece.

On our trip this past May(westbound) maybe half the men wore jackets to the Akademia Club welcome dinner and probably fewer than half those wore ties. At the Palais Pallavicini in Vienna I'd guess 90% wore jackets and maybe 70% wore ties. At the farewell diner at the Lobkowicz Palace it was someplace between those two.