The bulbs that get planted in the spring are available in spring…dahlias, cannas, etc.

The bulbs that are available now, daffodils, tulips, allium and lots of others are bulbs, that flower in spring but they must be planted now so they get the chilling period over winter that they need to set them up for flowering next spring.  These bulbs are also obviously winter hardy and will return every spring for years to some.  if you want them though, you’ll have to buy them and plant them from mid-September through October sometime.