A lot of condos in my neighborhood have elaborate fountains. Some keep them running close to year round somehow - I'm not sure if they heat the water, or what. But there are others who for whatever reason, shut theirs down earlier in the year.
Here in Vancouver we might get a lot of cherry blossoms in the spring (another informal signal that spring is near) but we do not get much in the way of leaves turning colour, at least not like I was used to back in Eastern Canada. What we do get though, is about 2 days of very strong wind and then the temperatures average about 10 degrees lower after that.
Anyhow, what signals do you notice that indicate fall is 'in the air'?