The times above are possibilities for visiting Sicily. Please comment on the pros and cons of these options. Would like nice weather (not too hot, not too cold, not much rain) and light crowds but when most things are still open. Also, I'd appreciate suggestions of things to see and do. We like hiking and bicycling (easy-moderate), kayaking, flora and fauna, art, culture, food. Don't want to spend a lot of time visiting ruins. Thanks!

The answer about crowds partly depends on where you are going. If you are going to Taormina or other cruise ship stops, September means crowds in Taormina, and perhaps early October too.

In terms of heat, seems to me hard to predict when the hot weather is finally gone but the significant storms haven't arrived. In my recollection, Sicily typically gets raked with a few violent thunderstorms in the transition from summer to fall. In other parts of the Med, that starts to be a risk starting with the 2d week of October. However, bad rains in Sicily usually clear up quickly, and it goes back to be pleasantly dry and warm, even into November. With the exception of swimming pools, most everything will be open and running into early November.

If you haven't already posted your question on the Tripadvisor forum for Sicily, I highly recommend it. There are native Sicilians who post there, and while you will get disclaimers about the inability to predict the weather for you -- there are just no "typical" experiences any more than you can count on absolutely -- the posters there are very very knowledgeable about Sicily, beyond tourist level. But tell them more precisely where in Sicily you are thinking of going.

My sister lives in Cefalù part of the year and October (first half) is her favourite month because the weather is usually nicer than in September and the crowds have gone. We have been 2nd half September and had nice weather most of the time (warm enough for the beach) with a half day of rain in Marsala and a day with dark clouds in the Madonie National Park.

For Sicily, my vote would be for later rather than earlier.

As for your thread on Croatia, I think you would be wise to consult historical climate data, which is available at
wunderground.com
and, of course, that climate date is summarized -- and presented along with "what to see / do / eat" -- in any decent guidebook. You should be able to find many at your local library.

It depends on what your opinion of 'not too hot' is. September will be warm. Mid or late October would be cooler. I was in Naples/ Amalfi Coast Early September and the heat was sometimes unbearable as we were sightseeing.

Warm/Hot temps are great for sunbathing, but not for hiking. shopping etc.