Hi Teddy - we've been to Corfu the last three Octobers and we've just booked flights for this year too.
Generally the weather is still very good - usually sunny with temps in the high 20s. However, there's always a chance of rain, and nothing is ever guaranteed with the weather.
On the plus side many of the spring flowers tend to have a second bloom and things start to look a lot fresher than the height of summer. You can also find some end-of-season bargains, the locals are starting to feel a bit demob happy (in a good way) and nowhere is as crowded.
Overall it's a really nice time to visit.