How to choose the best:
Onion

Touch

Look for a firm, plump bulb, which should feel heavy for its size, and be free of any damp spots.

Dry, papery skins are the goal here.

See

Avoid any bulbs with green sprouts or brown spots on the outside.

Some more details:

How to store

Store onions in a cool, dark place, such as the inside your cabinets. Outside of the fridge is best, to preserve quality.

Onions need all the same conditions as do garlic and shallots, so you’ll do well to simply store them together.

When it's in season

Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.