What is the typical weather like in Bilbao and San Sebastian during Mid October? Is it sweater weather? Do I need a rain coat? Thank you.
This site has what the weather was last year 2022 everyday in October and you can use the filter to look at other years to get an idea:
And I was there in July 2018 it was kind of cool that time of year where the rest of Spain is scorching.
That part of Spain tends to be wet and cool even in July. I'd want a warm layer and a rain jacket even in the middle of the summer. It may be quite temperate in the middle of the day, but it could cool off substantially at night.
I live near Bilbao and you never know about the weather here, it´s quite unreliable. If the wind changes to south (which lately happens more often), it´ll be nice and warm. But the predominant wind is north-west, that brings rain and cooler temperatures (and again, it rains less and less every year). I think it´ll be sweater weather and I would bring a raincoat, just in case, as it´s a very changeable weather but cool and often humid.