OPI Nail Lacquer, Lincoln Park After Dark, $8. This black-plum polish is a perennial favorite in nail salons everywhere -- maybe the sing-song name has something to do with it.

Sally Hansen Complete Salon Manicure, Dark Huemoor, $7. Halfway between blue and black is this intense crème enamel, perhaps the coolest nail polish you can find at a drugstore.

Deborah Lippmann, All Night Long, $20. Basic black polish is updated with a beautiful, bronze-y shimmer.

Why you need it: There comes a time every spring or summer when a flaming orange, bright blue or flamboyant violet mani-pedi just makes sense. Embrace the moment -- especially if you're going on vacation and/or wearing a sundress with sandals.

When to wear it: At the beach, at the pool, and whenever you need a dose of optimism.

Try...

Sally Hansen Color Therapy, Ja-Cozy, $7. An argan oil-infused nail polish in the most cheerful shade of cobalt.

OPI Nail Lacquer, Never a Dulles Moment, $8. OPI's latest collection, inspired by the show "Scandal," includes this opaque, sunny yellow.

Orly Gel FX Gel Nail Color, Invite Only, $5. Green is the 2017 Pantone Color of the Year; why not try a Kelly green mani?

Why you need it: Pastels may make you think of spring, but they're beautiful against winter whites and sun-tanned summer skin, too. Pastel nail polish gives any manicure a ladylike, clean look, and they're a beautiful base for nail art.

When to wear it: When you're tired of pale pink or nude; for Pinterest-worthy nail art. (Ombré! Polka dots! Stripes!)

Try...

JinSOON, Aero, $18. Picture this hip sky blue against light-colored denim -- gorgeous, right?

China Glaze, Partridge in a Palm Tree, $7. Milky mint is a pastel hue that always looks fresh.

Floss Gloss Nail Polish, Palazzo Pleasures, $8. This dusty lavender is the darker side of pastel, with just enough gray to look hip and modern.