We don't have a distinct autumn in my part of the world; it's more a transition between the wet and dry seasons. But we haven't had a real wet season again this year, so

That aside, the golden emperor cicadas are singing constantly through the day, something they weren't doing in January and February. I think it's their last hurrah. Also the northern greengrocer cicadas are kicking off their chorus earlier in the evening. In January, they started at 7.15pm and now they do it at 6.40pm. (I've been keeping notes.)