Chronicles of Whetherwhy
The Age of Enchantment

In Whetherwhy, everyone has magic inside them - and an affinity with either spring, summer, autumn or winter. But when Juniper discovers she is an Enchanter, someone who can wield all four seasons of magic, she is invited to study at Thistledown Academy. Unwilling to be left behind, her twin brother, Rafferty, follows her to the capital city. But monsters are creeping out of the shadows and dangers lurk in unexpected places.
Amid night markets and magic lessons, the twins realise there is more to enchantment than they ever could have imagined.