The short answer on 100 Degree Weather: pick one anchor piece, keep the palette to two colours, and let the shoes decide how formal the whole thing reads. The shoulder seam should sit on the bone, not past it. Hold it up to the light. Opacity is the thing product photography hides best. The groups below run from the decision that matters most to the ones you make afterwards.

What decides this is shoulder seam, sleeve length and opacity. Everything else is preference. Two from the first group show the range: Isabel Marant's Maria Top at $290, and La Garçonne's Stretch Jersey T-Shirt - Black at $265. The first is the considered buy; the second is the one to start with. The shoulder seam should sit on the bone, not past it. Hold it up to the light. Opacity is the thing product photography hides best. A higher price mostly buys materials and finishing, and occasionally it buys nothing at all.

If the top is the point, keep everything below it plain. From the second group, Few Moda's Tallulah Jacket ($248) is the one that earns its place, because it works in more than one context without being restyled. The third group is smaller and deliberately narrower, dresses, for the decisions you make after the main one. None of this needs the whole group. One piece from each is usually enough.

There are 20 pieces here from 15 brands, $60 to $445, all in stock when this was written. We would not buy all of them, and neither should you. VRG GRL's Phoebe Vest Top Chocolate at $60 is the low-risk way in, and simkhai.com's Noemi Sculpted Scuba Mini Dress at $445 only makes sense if this is a category you already use constantly. Read as a set, they get you close to 100 Degree Weather without any single purchase being compulsory. Nothing here is included because it is famous, and price is not used as a proxy for quality anywhere on this page. If you take one thing away: one considered purchase beats three hedged ones.