What is the average temperature in Kochi during mid-October?

Kochi, like most Indian coastal cities along the Arabian Sea, has moderate temperature without much fluctuation throughout the year (the link says Cochin because that was the old name of this city). In October it ranges from 25 to 29 degree Celsius. It's also one of the months when Kochi receives the most rainfall in most years (same link) so expect monsoon showers and high humidity throughout. Most of the October monsoon showers come from retreating monsoon winds which blow clouds from eastern to western sea-board, so Kochi comparatively will still receive less rainfall than east coast.

I haven't been to Kochi specifically in October but basically, be prepared for rains. Weather in general will be pleasant though.

Disregard the average stats, it's hitting 35 degrees C nowadays in the central parts of Kerala - which is where Kochi is.

October in Kerala is called the 2nd summer among the locals - it's because the post-monsoon coolness of September is gone, and it's a month away for the cooler winter. The main problem for any visitors will be humidity.

It's averaging 80% nowadays and will be the same around October too.

Note - I'm from Kerala so a bit of first-hand info there.

For what it's worth, it was about 31°C every day that I was in the Kochi area. A weather forecast a few days before I arrived told me to expect rain showers every day, but it only rained once and it was at night. Humidity was definitely high, which should be expected in the tropics. JoseK's estimate of around 80% humidity seems accurate to me. The temperature seemed to fit in what Mark Mayo found as the average range.