Haha Sally here.
It is erratic but Spring goes from Sept to November. However today in July I biked in short bike pants, a tee and a very light wind jacket. MY legs were bare from the knees to my short ankle socks. It is mid winter. Yet last Sunday I was in a ski jacket, a puffer, a beanie, gloves, a turtleneck, jeans, boots and thick socks!!
November can range hugely in temperatures too from sundress weather to sweater jeans and boots. Our summer won't be as warm as yours but our winter is not as cold either - it is different if you are in the South Island though.
I could wear Spring clothes most of the year with a few adjustments. I don't think about buying Spring clothes though - I tend to think of winter and summer.
