We are considering a cruise from Vilshofen to Budepest either in mid-August or mid-September. How hot is it along that stretch of the Danube in mid to late August? How much differnt is it by early to mid September?
Thanks!
Check climate tables for towns along your route at Time & Date website. They use the newest 30-year period.
Example Vienna: https://www.timeanddate.com/weather/austria/vienna/climate
Be aware that what they show as high temperature is NOT the max. temperature of days in this period. So day max temperatures can be much higher than shown there.
I use timeanddate.com for this sort of information, but not the monthly averages. I look at the actual, historical, day-by-day weather data so I can see how hot or how cold it might be at the time of my trip. I check the most recent five years, because there can be considerable year-to-year variation.
Here's where to look: https://www.timeanddate.com/weather/hungary/budapest/historic?month=8&year=2025
Use the pull-down box at the right, just above the graph, to see statistics for other months/years. Use the Search box near the upper right if you want to look at weather in other cities.
As you can see, August can be quite grim. Your odds will be better in September, but there could still be some rather hot days. The central European capitals can swelter in the summer, but they will probably not be super-hot every day, which is what you could run into in southern Italy or much of Spain.