It is autumn in Oct in Europe. Certainly there is no flowers to see, only red
leaves. Sometimes it rains.
Apr and May, in my opinion, is a good time to travel in Europe. I live in
Vienna. At the moment, the temp. is around 7 - 20C. In May, it is usually
around 25-28C in day time. Streets and gardens are decorated with flowers. And it is usually sunny in Summer.
Remark: As air-conditioners are not common in middle and nothern Europe, 28C may be VERY HOT for HK people.