Granted you are from the UK so I will let it slide but early October was fairly cool haha. What is weird is both my trips to the Jacksonville Zoo were on days in which it was unusually and unseasonably cool both back in March and late September. 2013 was a fairly wet cool year for the entire southeast compared to say 2011.
I was actually told a couple of times that October in Florida this year was unseasonably warm, meaning certain species that would normally be about weren't (such as American Oystercatchers). Obviously varied quite a bit across the South!
Certainly every day I was in Florida ended up warmer and often drier than forecast. Atlanta, not so much!
The reason I went back in September because it was bone chilling cold during spring break (at least to me as a spoiled Southerner). On my second trip to Jacksonville Zoo, It wasn't cold by any stretch of the imagination it just wasn't "florida warm" for late September. Now it certainly may have been warmer in October I haven't been back to Florida nor do I keep up with its temp.
Was intrigued by this so had a quick Google - accuweather.com's very handy! The lowest temperature in Jacksonville in September was a minimum of 63°F/17°C on the 30th - even the coldest day had a maximum of 75°F/25°C - you really are spoiled if that's a cold month for you!
On the 10th October when I was there it got as warm as 82°F/28°C - on the same day back home the maximum was 52°F/11°C!
March (spring break) was when I went to the zoo and it was so bone chilling cold (unseasonably). It was so cold I couldn't enjoy the Zoo. The day I went in March was the 26th because I found my ticket stubs. The high that day was 55 degrees Fahrenheit which is a cold day at the zoo or the beach.
I don't remember the day I went back to the zoo in September it was cool (for that time of year) that evening on the beach but it was a great day at the Zoo.
You want a day at the Zoo? Come join us southern zoochatters in August when its 101 Fahrenheit with extremely high humidity. Going to the zoo on those days requires either strength or stupidity probably both. And all the animals take those days as nap days.