Sweet onions, available from February to August are known for their mild, sugary, taste. They are high in water and sugar.  And contain more sugars and fewer sulfur-containing compounds than other onions do. 

When buying, look for sweet onions with light golden-brown in color, a shiny tissue-thin skin and firm, tight, dry necks.  When cut into, they should have a creamy white interior. Avoid onions that have soft spots or surface bruises.

 

They are often named by geographic origin and described as being sweet.

 

The best known are:

Vidalia from Georgia, Walla Walla from Washington, Maui from Hawaii, Imperial from California, Carzalia from New Mexico, The Texas Spring or Supersweet from Texas, OSO Sweets from Chile, South America

 

How to tell in the market whether an onion is sweet - Sweet onions have a thinner, lighter color skin than other onions and tend to be more fragile.