I will be in Madrid, Sevilla, and Barcelona from 7 to 23 October. What can I expect for weather? It will impact what clothes I bring.

That's a really difficult question . In the 6 years I lived in Madrid I can remember having temperatures up in the 80s as well as very cold weather .. October is that sort of autumn cusp between summer and winter . I would bring a selection .. maybe polo shirts , a jumper or sweatshirt . Definitely a jacket . Not that helpful an answer but it is a difficult month to predict in Madrid and Barcelona . Sevilla is likely to be quite mild being so far South , but I'd still pack a jacket .

Thanks Steve! I appreciat your input. I have travelled to Spain four time before, but never in one of the "shoulder seasons" when the weather and proper clothes are so unclear.

Dear Friend,

As madrilean, I can tell you that the month of October can vary significantly depending on the year. Earlier this month tends to moderate temperatures, and even hot. Here we call "The little summer of Sant Michael" by the saint in the Catholic calendar matches during those days. And also true, if it is a rainy early fall tends to rain a lot but not too cold. In Spain for its Mediterranean climate call this weather phenomenon as the "Cold Drop", with very heavy downpours, hail and storms like your American Midwest. But if the year is very dry weather.
Throughout the month and by the day, begins to cooler. Finally after November is approaching and so the winter.

I hope I helped.

Greetings.