October is not one climate across India.
The northeast monsoon affects parts of southern peninsular India during October to December, as described in the India Meteorological Department’s research journal.
That is seasonal context, not a forecast for your event.
Check your city’s forecast near the date. For warmth, assess the complete outfit, including lining and layers. For rain risk, consider an above-ground hem, a manageable umbrella and footwear suitable for the route.
For a cooler evening, carry a layer you can actually secure.
A fabric name can mislead. Georgette describes a fabric construction and may use different fibres; a light surface does not prove breathability. Cotton can feel very different depending on weave and lining.
Test the actual garment indoors for a while, including sitting, before committing to a long day.