1 Travel based on your interests, I love Europe in October, some locations will be warmer than others; but what are your plans, the beach or museums or wandering the streets taking in the sights?
2 Averaging the Oct & Nov temps: Lisbon: 68/56, Budapest 55/43, Rome 67/49, Paris 66/43, Prague 56/40, none unbearable.
3 As you get deeper into Nov the differences in temps begin to close; by mid-November there is only a 2F difference between Budapest and Paris.
4 For better prices, head East the dollar is strong, but the world is in an inflationary trend and prices are up everywhere so the exchange rate savings is negated to a degree.
5 After 19 Nov the Christmas Markets will be open, and the temperature is part of the experience (google for the best market awards).