I find the answers fascinating and I am nodding my head along with most! I used to live near Runcarla and Irina and Dee (actually, I lived in a small city smack dab in between theirs!) so I agree with what they said re the big distinction between summer and winter, the variability and unpredictability of spring weather in those parts, and also the need for at least a few distinctly "fall" items (as a rule.) In fact, when I lived there, I used to sort my closet into six sub-seasons:
Now I live in a more temperate climate and more of my clothes are cross-seasonal but it has taken me some time to figure this out, and start buying for the new reality. The items that I wear most now include:
Light merino wool sweaters (and merino gear). I wear the sweaters 3 seasons and the gear all year.
Jeans and dressy pants in lightweight wool or similar. In summer, I do switch out for more cropped styles and for lighter weight fabrications or lighter washes and I will wear white jeans much more often. In my former climate, I almost never wore jeans in summer. Too hot!
Cotton sweaters (more of a spring/ summer/ fall staple).
Coats of all kinds, and I find I need a lot more options for true outerwear here! Like Star, I am out in the elements every day and I find that different weights of puffer coat, different types of wool coat, and -- of course! -- many different styles and types of raincoat are key to comfort!
I tend to switch out my footwear -- sneakers and oxfords in spring/ fall; sandals in summer (with some lighter sneakers or oxfords), and boots/ booties in fall/ winter.
I wear skirts and dresses and sleeveless or short-sleeved tops more. in summer.