Style Director Harper's Bazaar US, Joanna Hillman, before Peter Som, NYC, September 2012.
With the change of season only a month away (today in London, the beginning of spring feels a long, long way, and many more coat-outings, away!), layering like Joanna has done here is one solution for dressing for tricky weather. Another solution is having a temperature-controlled car and driver on hand for as soon as you leave the house/office (we can only dream!) :)
Recreate Joanna's look (kind of):
Brightly coloured blazer/jacket:Rag & Bone Jefferson blazer, Helmut Lang reversible leather and jersey biker jacket, Carven patch pocket jacket,  Alice + Olivia Elyse blazer, BB Dakota Arlene blazer, Joseph emerald green blazer, or Hilfiger Denim bright blazer
White dress/shirtdress (layer with a jacket/pants/jeans now and for spring, and wear bare for summer): Jenni Kayne sleeveless shirtdress, 3.1 Phillip Lim floral jacquard dress, Equipment Kennedy dress, RDM by Rue du Mail poplin tunic dress, Haider Ackermann Addlington cotton shirt, Calvin Klein Collection Nemuro shirtdress, or 3.1 Phillip Lim pintucked flirt dress
Black cropped pants: DKNY Perry cropped trousers,Vince cropped flare pants, Topshop split front skinny trousers or ASOS cropped pants