suspicious or auspicious?

I've come across a sign that appears to be signalling a change:

My first instinct was these red leaves were suspiciously foreshadowing the end of summer (and therefore, from my Calgarian experience, the beginning of the brown season). But, I think they're actually a good sign. Fall is supposed to be the best season out here, so that's gotta be an improvement on (foggy) summer.* And, we were here last fall at Halloween, and it was still sunny with bright fall colours, so that's a sign of some good months to come.

* I know, I know - it feels so wrong that summer isn't the 'best' season!